#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <climits>
#include <algorithm>
using namespace std;

long long int maxSubArraySum(long int a[],long int size)
{
    int max_so_far = LLONG_MIN, max_ending_here = 0;

    for (long int i = 0; i < size; i++)
    {
        max_ending_here = max_ending_here + a[i];
        if (max_so_far < max_ending_here)
            max_so_far = max_ending_here;

        if (max_ending_here < 0)
            max_ending_here = 0;
    }
    return max_so_far;
}
int main() {
    long int n,x,y;
    cin>>n>>x>>y;
    long int lat[n],lon[n],ht[n],val[n];
    for(long int i=0;i<n;i++){
        cin>>lat[i]>>lon[i]>>ht[i]>>val[i];
    }
    for(long int i=1;i<n;++i)
    {
        for(long int j=0;j<(n-i);++j)
            if(ht[j]>ht[j+1])
            {
                ht[j] ^= ht[j+1];
                ht[j+1] ^= ht[j];
                ht[j] ^= ht[j+1];
                val[j] ^= val[j+1];
                val[j+1] ^= val[j];
                val[j] ^= val[j+1];
            }
    }
    cout<<maxSubArraySum(val, n);
    return 0;
}