import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class D {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni();
		int x = ni(), y = ni();
		int[][] co = new int[n][];
		for(int i = 0;i < n;i++){
			co[i] = new int[]{ni(), ni(), ni(), ni()};
		}
//		Arrays.sort(co, new Comparator<int[]>() {
//			public int compare(int[] a, int[] b) {
//				return a[2] - b[2];
//			}
//		});
		StaticRangeTreeRMQ2 st = new StaticRangeTreeRMQ2(co, 200005);
//		for(int i = 0;i < n;i++){
//			st.update(co[i][0], co[i][1], Long.MAX_VALUE / 2);
//		}
		mergesort(co, 0, n);
		long max = Long.MIN_VALUE;
		long[] dp = new long[n];
		for(int i = 0;i < n;i++){
			long min = -st.min(co[i][0]-x, co[i][0]+x+1, co[i][1]-y, co[i][1]+y+1);
			long val = co[i][3] + Math.max(min, 0);
			dp[i] = val;
			st.update(co[i][0], co[i][1], -dp[i]);
			max = Math.max(max, dp[i]);
		}
		out.println(max);
	}
	
	private static int[][] stemp = new int[200005][];
	
	public static void mergesort(int[][] a, int s, int e)
	{
		if(e - s <= 1)return;
		int h = s+e>>1;
		mergesort(a, s, h);
		mergesort(a, h, e);
		int p = 0;
		int i= s, j = h;
		for(;i < h && j < e;)stemp[p++] = a[i][2] < a[j][2] ? a[i++] : a[j++];
		while(i < h)stemp[p++] = a[i++];
		while(j < e)stemp[p++] = a[j++];
		System.arraycopy(stemp, 0, a, s, e-s);
	}
	
	public static void mergesort0(int[][] a, int s, int e)
	{
		if(e - s <= 1)return;
		int h = s+e>>1;
		mergesort0(a, s, h);
		mergesort0(a, h, e);
		int p = 0;
		int i= s, j = h;
		for(;i < h && j < e;)stemp[p++] = a[i][0] < a[j][0] || a[i][0] == a[j][0] && a[i][1] < a[j][1] ? a[i++] : a[j++];
		while(i < h)stemp[p++] = a[i++];
		while(j < e)stemp[p++] = a[j++];
		System.arraycopy(stemp, 0, a, s, e-s);
	}
	
	public static class StaticRangeTreeRMQ2 {
		public int M, H, N;
		public SegmentTreeRMQL[] st;
		public int[][] maps;
		public long[][] vals;
		public int[] count;
		public long I = Long.MAX_VALUE;
		
		public StaticRangeTreeRMQ2(int[][] co, int n)
		{
			N = n;
			M = Integer.highestOneBit(Math.max(N-1, 1))<<2;
			H = M>>>1;
			
			mergesort0(co, 0, co.length);
//			Arrays.sort(co, new Comparator<int[]>() { // x asc
//				public int compare(int[] a, int[] b) {
//					if(a[0] != b[0])return a[0] - b[0];
//					return a[1] - b[1];
//				}
//			});
			maps = new int[M][];
			vals = new long[M][];
			st = new SegmentTreeRMQL[M];
			count = new int[M];
			for(int i = 0;i < co.length;i++){
				count[H+co[i][0]]++;
			}
			int off = 0;
			for(int i = 0;i < n;i++){
				maps[H+i] = new int[count[H+i]];
				for(int j = 0;j < count[H+i];j++,off++){
					maps[H+i][j] = co[off][1];
				}
				st[H+i] = new SegmentTreeRMQL(count[H+i]);
			}
			
			for(int i = H-1;i >= 1;i--){
				if(maps[2*i+1] == null){
					maps[i] = maps[2*i];
					count[i] = count[2*i];
				}else{
					count[i] = count[2*i] + count[2*i+1];
					maps[i] = new int[count[i]];
					int l = 0;
					for(int j = 0, k = 0;j < count[2*i] || k < count[2*i+1];l++){
						if(j == count[2*i]){
							maps[i][l] = maps[2*i+1][k++];
						}else if(k == count[2*i+1]){
							maps[i][l] = maps[2*i][j++];
						}else if(maps[2*i][j] < maps[2*i+1][k]){
							maps[i][l] = maps[2*i][j++];
						}else if(maps[2*i][j] > maps[2*i+1][k]){
							maps[i][l] = maps[2*i+1][k++];
						}else{
							maps[i][l] = maps[2*i][j++];
							k++;
						}
					}
					if(l != count[i]){ // uniq
						count[i] = l;
						maps[i] = Arrays.copyOf(maps[i], l);
					}
				}
				if(count[i] <= 25){ // 10% faster
					vals[i] = new long[count[i]];
					Arrays.fill(vals[i], Long.MAX_VALUE / 2);
				}else{
					st[i] = new SegmentTreeRMQL(count[i]);
				}
			}
		}
		
		public void update(int x, int y, long v)
		{
			outer:
			for(int pos = H+x;pos >= 1;pos>>>=1){
				if(st[pos] != null){
					int ind = Arrays.binarySearch(maps[pos], y);
					if(ind >= 0){
						st[pos].update(ind, v);
						continue;
					}
				}else{
					for(int i = 0;i < count[pos];i++){
						if(maps[pos][i] == y){
							vals[pos][i] = v;
							continue outer;
						}
					}
				}
				throw new RuntimeException(String.format("access to non-existing point : (%d,%d):%d", x, y, v));
			}
		}
		
		public long min(int xl, int xr, int yl, int yr) { return min(xl, xr, yl, yr, 0, H, 1); }
		
		public long min(int xl, int xr, int yl, int yr, int cl, int cr, int cur)
		{
			if(xl <= cl && cr <= xr){
				if(st[cur] != null){
					int indl = Arrays.binarySearch(maps[cur], yl);
					int indr = Arrays.binarySearch(maps[cur], yr);
					if(indl < 0)indl = -indl - 1;
					if(indr < 0)indr = -indr - 1;
					return st[cur].minx(indl, indr);
				}else{
					long min = I;
					for(int i = 0;i < count[cur] && maps[cur][i] < yr;i++){
						if(maps[cur][i] >= yl && vals[cur][i] < min) min = vals[cur][i];
					}
					return min;
				}
			}else{
				int mid = cl+cr>>>1;
				long ret = I;
				if(cl < xr && xl < mid)ret = Math.min(ret, min(xl, xr, yl, yr, cl, mid, 2*cur));
				if(mid < xr && xl < cr)ret = Math.min(ret, min(xl, xr, yl, yr, mid, cr, 2*cur+1));
				return ret;
			}
		}
	}
	
	public static class SegmentTreeRMQL {
		public int M, H, N;
		public long[] st;
		
		public SegmentTreeRMQL(int n)
		{
			N = n;
			M = Integer.highestOneBit(Math.max(N-1, 1))<<2;
			H = M>>>1;
			st = new long[M];
			Arrays.fill(st, 0, M, Long.MAX_VALUE/2);
		}
		
		public SegmentTreeRMQL(long[] a)
		{
			N = a.length;
			M = Integer.highestOneBit(Math.max(N-1, 1))<<2;
			H = M>>>1;
			st = new long[M];
			for(int i = 0;i < N;i++){
				st[H+i] = a[i];
			}
			Arrays.fill(st, H+N, M, Long.MAX_VALUE);
			for(int i = H-1;i >= 1;i--)propagate(i);
		}
		
		public void update(int pos, long x)
		{
			st[H+pos] = x;
			for(int i = (H+pos)>>>1;i >= 1;i >>>= 1)propagate(i);
		}
		
		private void propagate(int i)
		{
			st[i] = Math.min(st[2*i], st[2*i+1]);
		}
		
		public long minx(int l, int r){
			long min = Long.MAX_VALUE;
			if(l >= r)return min;
			while(l != 0){
				int f = l&-l;
				if(l+f > r)break;
				long v = st[(H+l)/f];
				if(v < min)min = v;
				l += f;
			}
			
			while(l < r){
				int f = r&-r;
				long v = st[(H+r)/f-1];
				if(v < min)min = v;
				r -= f;
			}
			return min;
		}
		
		public long min(int l, int r){ return l >= r ? 0 : min(l, r, 0, H, 1);}
		
		private long min(int l, int r, int cl, int cr, int cur)
		{
			if(l <= cl && cr <= r){
				return st[cur];
			}else{
				int mid = cl+cr>>>1;
				long ret = Long.MAX_VALUE;
				if(cl < r && l < mid){
					ret = Math.min(ret, min(l, r, cl, mid, 2*cur));
				}
				if(mid < r && l < cr){
					ret = Math.min(ret, min(l, r, mid, cr, 2*cur+1));
				}
				return ret;
			}
		}
		
		public int firstle(int l, long v) {
			int cur = H+l;
			while(true){
				if(st[cur] <= v){
					if(cur < H){
						cur = 2*cur;
					}else{
						return cur-H;
					}
				}else{
					cur++;
					if((cur&cur-1) == 0)return -1;
					if((cur&1)==0)cur>>>=1;
				}
			}
		}
		
		public int lastle(int l, long v) {
			int cur = H+l;
			while(true){
				if(st[cur] <= v){
					if(cur < H){
						cur = 2*cur+1;
					}else{
						return cur-H;
					}
				}else{
					if((cur&cur-1) == 0)return -1;
					cur--;
					if((cur&1)==1)cur>>>=1;
				}
			}
		}
	}

	
	void run() throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
	}
	
	public static void main(String[] args) throws Exception { new D().run(); }
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}