using System;
using System.Linq;
class Program {
    static void Main() {
        Console.Write("Enter string: ");
        string str = Console.ReadLine();
        var maxChar = str.GroupBy(c => c)
                         .OrderByDescending(g => g.Count())
                         .First().Key;
        Console.WriteLine("Max Occurring: " + maxChar);
    }
}