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-----
5
2 6 1 4 5

-----Sample Output-----
YES

The elements are pairwise distinct.

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