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;
#define ll long long int
#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,a) REP(i,0,a)
#define rev(s) reverse(s.begin(),s.end())
#define pb push_back

 
int main() 
{   
	

    
	
	 ll n,i,j;
	 ll a[n];
	 cin>>n;
	 rep(i,n)
	 {
	 cin>>a[i];
    }
    bool b=0;

    rep(i,n)
    {
    	REP(j,1,n){
    		if(a[i]!=a[j]&&i!=j){
    			cout<<"YES";
    			b=1;
    			break;
    		}
    	}
    }
    if(b==0){
    	cout<<"NO";
    }


	   return 0;
	
}