p02779 AtCoder Beginner Contest 154 - Distinct or Not
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
```python
#154_C
n = int(input())
a = set(input().split())
print('YES' if len(a) == n else 'NO')
```