using System;

public class Program

{

    public static void Main()

    {

        //Approach: Check each no with all next numbers in array

        //Integer array havin numbers range 1-10

        int[] arr = {3,4,5,6,2,1,4,7,8,9};

        int len = arr.Length;

        for(int i=0; i<len ; i++){

            for(int j=i+1; j<len ; j++){

                if(arr[i] == arr[j]){

                    Console.WriteLine("Duplicate found");

                    return;

                }       

        }           

        }

        Console.WriteLine("Duplicate not found");

    }

}