BA_L

using System;

namespace zadL
{

    class Program
    {   
        static char LastSymbol(string pattern)
        {
            char sym = pattern[pattern.Length - 1];
            return sym;
        }

        static string Prefix(string pattern)
        {
            string pref = "";
            for(int i=0; i<pattern.Length-1;i++)
            {
                pref += pattern[i];
            }
            return pref;
        }

        static int SymbolToNumber(char symbol)
        {
            if (symbol == 'T') return 3;
            else if (symbol == 'G') return 2;
            else if (symbol == 'C') return 1;
            else return 0; // =='A'
         

        }

        static int PatternToNumber(string pattern)
        {
            int cnt = 0;
            if (pattern.Length == 0) return 0;
            char symbol;
            string prefix;
            symbol = LastSymbol(pattern);
            prefix = Prefix(pattern);

            return 4 * PatternToNumber(prefix) + SymbolToNumber(symbol);
        }
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
        }
    }
}