/*	
 * Code Author: Anamika Modi
 * DA-IICT
 */
import java.io.*;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.util.*;


 public class code1 {

	static double eps=(double)1e-6;
	static long mod=(int)1e9+7;
	public static void main(String args[]){
		InputReader in = new InputReader(System.in);
		OutputStream outputStream = System.out;
		PrintWriter out = new PrintWriter(outputStream);
		//----------My Code----------
		int a[]=new int[26];
		for(int i=0;i<26;i++){
			a[i]=in.nextInt();
		}
		String sp[]=in.nextLine().split(" ");
		int total=0;
		for(int i=0;i<sp.length;i++){
			int sum=0;
			for(int j=0;j<sp[i].length();j++){
				if(sum<a[sp[i].charAt(j)-'a'])
				sum=a[sp[i].charAt(j)-'a'];
			}
			total+=sum*sp[i].length();
		}
		System.out.println(total);
		//---------------The End------
		
		out.close();
	
	}
	static void rec(ArrayList<ArrayList<Integer>> arr,ArrayList<Integer> a,int position1,int position2){
		   
		   if(position1==position2){
		       arr.add(new ArrayList<Integer>());
		        for(int i=0;i<a.size();i++){
		            arr.get(arr.size()-1).add(a.get(i));
		        }
		    }
		    else{
		    for(int i=position1;i<=position2;i++){
		   //System.out.println(position1+" "+i);
		    swap(a,position1,i);
		    rec(arr,a,position1+1,position2);
		    //System.out.println(position1+" "+i);
		    swap(a,position1,i);
		    }
		    }
		}
		static void swap(ArrayList<Integer> a,int p,int q){
		   // System.out.println(a.get(p)+" "+a.get(q)+"before swap");
		    int temp=a.get(p);
		    a.set(p,a.get(q));
		    a.set(q,temp);
		  //  System.out.println(a.get(p)+" "+a.get(q)+"after swap");
		}


	static int recursiveBinarySearch(int[][] sortedArray, int start, int end, int key) {

		if (start <= end) {
			int mid = start + (end - start) / 2; 
			if (key < sortedArray[mid][0]) {
				return recursiveBinarySearch(sortedArray, start, mid, key);

			} else if (key > sortedArray[mid][0]) {
				return recursiveBinarySearch(sortedArray, mid+1, end , key);

			} else {
				return mid;  
			}
		}
		return -(start + 1); 
	}

	static long modulo(long a,long b,long c) {
		long x=1;
		long y=a;
		while(b > 0){
			if(b%2 == 1){
				x=(x*y)%c;
			}
			y = (y*y)%c; // squaring the base
			b /= 2;
		}
		return  x%c;
	}
	static long gcd(long x, long y)
	{
		long r=0, a, b;
		a = (x > y) ? x : y; // a is greater number
		b = (x < y) ? x : y; // b is smaller number
		r = b;
		while(a % b != 0)
		{
			r = a % b;
			a = b;
			b = r;
		}
		return r;
	}
	static class Pair implements Comparable<Pair>{
		int x;
		int y;
		//int i;
		Pair(int xx,int yy){
			x=xx;
			y=yy;
			//i=ii;
		}
		@Override
		public int compareTo(Pair o) {
			return Integer.compare(this.x,o.x);
		
		}
		
	}
	static class InputReader {
		public BufferedReader reader;
		public StringTokenizer tokenizer;

		public InputReader(InputStream inputstream) {
			reader = new BufferedReader(new InputStreamReader(inputstream));
			tokenizer = null;
		}

		public String nextLine(){
			String fullLine=null;
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					fullLine=reader.readLine();
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
				return fullLine;
			}
			return fullLine;
		}
		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}
		public long nextLong() {
			return Long.parseLong(next());
		}
		public int nextInt() {
			return Integer.parseInt(next());
		}
	}
}