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 Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int i, j, N, T=0;
        int A[] =new int[1000000000];
        N = scan.nextInt();
        for(i=0; i<N; i++){
            A[i] = scan.nextInt();
        }
        for(i=0; i<N-1; i++){
            for(j=i+1; j<N; j++){
                if(A[i]==A[j]){
                    T++;
                }
            }
        }
        if(T==0){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
}