Problem:
Score : 300 points

Problem Statement

Given is a sequence of integers A_1, A_2, ..., A_N.
If its elements are pairwise distinct, print YES; otherwise, print NO.

Constraints

2 ≤ N ≤ 200000

1 ≤ A_i ≤ 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 ... A_N

Output

If the elements of the sequence are pairwise distinct, print YES; otherwise, print NO.

Sample Input 1

5
2 6 1 4 5

Sample Output 1

YES

The elements are pairwise distinct.

Sample Input 2

6
4 1 3 1 6 2

Sample Output 2

NO

The second and fourth elements are identical.

Sample Input 3

2
10000000 10000000

Sample Output 3

NO

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;

class Code_01
{

    public static void Main()
    {
        string N = Console.ReadLine();
        string Lines = Console.ReadLine();
        int Num = int.Parse(N);
        int[] Ar = new int[Num];
        bool OK = true;
        for (int i = 0; i < Num; i++)
        {
            Ar[i] = int.Parse(Lines.Split(' ')[i]);
            Console.WriteLine(Ar[i]);
        }
  
        Array.Sort(Ar);
   
        for (int j = 0; j < Num; j++)
        {
            if (j != 0)
            {
                if (Ar[j - 1] == Ar[j])
                {
                  
                    OK = false;
                }
            }

        }
        if (OK == true)
        {
            Console.WriteLine("YES");
        }
        else if (OK == false)
        {
            Console.WriteLine("NO");
        }

    }


}