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 JavaScript (node.js v5.12) (judge verdict: Time Limit Exceeded)

function Main(input) {
	var str = input;
	var ans = "YES";
	var c = 0;
	str = str.split("\n");
	var l = str[1].split(" "); 
	loop:
	for(var j =0;j< l.length-1;j++){	
 		for(var i =1; i<l.length;i++){
 			 if(l[j]===l[i+c]){
	 			ans = "NO";
	 			break loop;
 			}	 	
 		}
 		c++;
	} 	
	console.log(ans);
}
 //*おまじない
Main(require("fs").readFileSync("/dev/stdin", "utf8"));