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 sc = new Scanner(System.in);
		byte n = sc.nextByte(),c=0,i=0,j=0;
		int a[] = new int [n];
 
		while(c<n) {
			a[c] = sc.nextInt();
			c++;
		}
		sc.close();
 
		for(;i<n;i++) {
			for(;j<n;j++) {
				if(i==j) continue;
				if(a[i]==a[j]) {
					System.out.println("NO");
					return ;
				}
			}
		}
 
		System.out.println("YES");
		
	}
 
}