using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static void Main(String[] args) {
        string[] h_temp = Console.ReadLine().Split(' ');
        int[] h = Array.ConvertAll(h_temp,Int32.Parse);
        string word = Console.ReadLine();
        int len = word.Length;
        char[] cha = word.ToCharArray();
        int max = 0;
        for (int i = 0; i < len ; i++) {
            int c = (int) cha[i] - 97;
            if (max < h[c]) max = h[c];
        }
        
        int area = len*max;
        Console.WriteLine(area);
    }
}