using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace PDF
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] h_temp = Console.ReadLine().Split(' ');
            int[] h = Array.ConvertAll(h_temp, Int32.Parse);
            string word = Console.ReadLine();

            var chars = word.ToCharArray();

            var width = chars.Length;

            var height = chars.Select(x => h[(int)x - 97]).Max();

            Console.WriteLine(width * height);

        }
    }
}