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 (GCC 5.4.1) (judge verdict: Runtime Error)

#include <stdio.h>
#include <string.h>

static struct{
	unsigned h : 1;
}obj[100010100];

int main()
{
	long i,N,tmp;
	i=0;
	scanf("%ld",&N);
	//for(i=0;i<100010100;i++)obj[i].h=0;
	for(i=0;i<N;i++){
		scanf("%ld",&tmp);
		//printf("%u ",obj[tmp].h);
		if(obj[tmp].h==0){
			obj[tmp].h=1;
		}
		else{
			printf("NO\n");
			return 0;
		}
	}
	
	printf("YES\n");
	return 0;
}