// CodeEval.com
// Medium - First Non-Repeated Character
// Score: 56.158

using System;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;

class Program
{
    static int Main(string[] args)
    {
        using (StreamReader reader = File.OpenText(args[0]))
        {
            while (!reader.EndOfStream)
            {
                var line = reader.ReadLine();

                var result = line.ToCharArray().GroupBy(l => l).Where(l => l.Count() == 1).Select(l => l.Key);

                Console.WriteLine(result.First());
            }
        }
        return 0;
    }
}