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`.

Examples

Input

5
2 6 1 4 5


Output

YES


Input

6
4 1 3 1 6 2


Output

NO


Input

2
10000000 10000000


Output

NO
Solution:

n=int(input())
l=list(map(int,input().split()))
s=set(l)
print('YES'if len(s)==len(l)else 'NO')