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();
        
        var maxH = -1;
        
        foreach (char c in word.ToCharArray())
            if (h[c - 'a'] > maxH)
                maxH = h[c - 'a'];
        
        Console.WriteLine(maxH * word.Length);
    }
}