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 h[] = new int[n];
        for(int h_i=0; h_i < n; h_i++){
            h[h_i] = in.nextInt();
        }
        String alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toLowerCase();
        String word = in.next();
        int max = 0;
        for(int i=0; i < word.length(); i++){
            if(max < word.length()*(alpha.indexOf(word.charAt(i))+1)) max = word.length()*(alpha.indexOf(word.charAt(i))+1);
        }
        System.out.println(max);
    }
}