Score : 300 points
Given is a sequence of integers A_1, A_2, ..., A_N.
If its elements are pairwise distinct, print YES
; otherwise, print NO
.
Input is given from Standard Input in the following format:
N A_1 ... A_N
If the elements of the sequence are pairwise distinct, print YES
; otherwise, print NO
.
5 2 6 1 4 5
YES
The elements are pairwise distinct.
6 4 1 3 1 6 2
NO
The second and fourth elements are identical.
2 10000000 10000000
NO