using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class W411
    {
        public static void Main(string[] ae)
        {
            int[] inp = Console.ReadLine().Split(' ').Select(c => int.Parse(c)).ToArray();
            string word = Console.ReadLine();
            int max = -1;
            foreach (char a in word.ToCharArray())
            {
                if (inp[a - 97] > max)
                    max = inp[a - 97];
            }
            Console.WriteLine(max * word.Length);
        }
    }