using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        Console.WriteLine("Enter a string");

        string str = Console.ReadLine();

        bool unique = isUnique(str);

        Console.WriteLine("Unique " + unique);

    }

    public static bool isUnique(string s){

        bool[] chars = new bool[128];

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

            char c = s[i];

            if(chars[c])

                return false;

            chars[c] = true;

        }

        return true;

    }

}