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 mh = 0;
        foreach (var c in word) {
            mh = Math.Max(mh, h[c - 'a'] );
        }
        
        Console.WriteLine(mh * word.Length);
    }
}