import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

     public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = 26;
        int res = 0, count = 0, big = 0;
        
        int h[] = new int[n];
        for(int h_i=0; h_i < n; h_i++){
            h[h_i] = in.nextInt();
        }
        String word = in.next();   
        int large[] = new int[word.length()];
        char c[] = word.toCharArray();
        char alpha[] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
        for(int i = 0; i < c.length; i++)
            {
               if(c[i] == alpha[i])
                {
            	   count++;            	   
                   large[i] = h[i];             
                
                 }                   
             }
        for(int i = 0; i < large.length; i++)
		{			
				if(large[i] > big)
				{
					big = large[i];
				}
		}
       
           res = (big*count);
           System.out.println(res);
        
    }
}