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++14 (GCC 5.4.1) (judge verdict: Runtime Error)

#include<bits/stdc++.h>
using namespace std;

template<typename T, typename U> bool chmin(T &a, const U &b) {
	return (a > b ? a = b, true : false);
}
template<typename T, typename U> bool chmax(T &a, const U &b) {
	return (a < b ? a = b, true : false);
}

typedef long long ll;

#define writeln(n) cout<<n<<"\n";

typedef pair<int, int> P;
typedef pair<string, int> Psi;

ll d[100000000+5];
int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	ll n;
	cin>>n;

	for(int i=0; i<n; i++){
		int tmp;cin>>tmp;

		if(d[tmp] ==0){
			d[tmp]++;
		}else {
			writeln("No");
			return 0;
		}
	}
	writeln("Yes");



}