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();
            string[] alphabet = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z" };


            char[] charArray = word.ToCharArray();

            int largestNum = 0;
            int theNum = 0;

            for (int i = 0; i < charArray.Length; i++)
            {

                for (int ii = 0; ii < alphabet.Length; ii++)
                {
                    if (charArray[i].ToString() == alphabet[ii].ToString())
                    {
                        theNum =  h[i];

                        if (theNum > largestNum)
                        {
                            largestNum = theNum;
                        }
                    }
                }
              
            }

            int blockHeight = largestNum * largestNum;
            Console.WriteLine(blockHeight);
    
    }
     
}