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 width = word.Length;
            int height = 0;
            foreach(char c in word)
            {
                int offset = c - 'a';
                int thisHeight = h[offset];
                if (thisHeight > height)
                    height = thisHeight;
            }

            Console.WriteLine(width * height);
    }
}