import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;
import java.io.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

/**
 *
 * @author TuAnh
 */
public class pdf {

    private static final int MODE = 2;
    private static int a[]= new int[26];

    public static void main(String agrs[]) throws Exception {
        for(int i=0;i<26;i++)a[i]=inp.nextInt();
        String st=inp.nextLine();
        int n=st.length();
        int h=0;
        for(int i=0;i<n;i++)h=Math.max(h,a[st.charAt(i)-'a']);
        pw.println(n*h);
        df();
    }

    /**
     * ******************************************
     */

    static class FastScanner {

        BufferedReader br;
        StringTokenizer st;

        public FastScanner() {
            if (MODE == 1) {
                FileInputStream f;
                try {
                    f = new FileInputStream("e:\\spoj\\input.txt");
                    br = new BufferedReader(new InputStreamReader(f));
                } catch (FileNotFoundException ex) {
                    br = new BufferedReader(new InputStreamReader(System.in));
                }
            } else {
                br = new BufferedReader(new InputStreamReader(System.in));
            }
            st = new StringTokenizer("");
        }

        String next() throws Exception {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
            return st.nextToken();
        }

        int nextInt() throws Exception {
            return Integer.parseInt(next());
        }

        public long nextLong() throws Exception {
            return Long.parseLong(next());
        }

        public String nextLine() throws Exception {
            return br.readLine();
        }

        public double nextDouble() throws Exception {
            return Double.parseDouble(next());
        }

        public boolean ready() throws Exception {
            return br.ready();
        }
    }
    private static void df(){
        pw.flush();pw.close();
    }
    private static FastScanner inp = new FastScanner();
    private static PrintWriter pw = new PrintWriter(System.out);

}