Score : $300$ points
There are $N$ integers written on a blackboard. The $i$-th integer is $A_i$.
Takahashi will repeatedly perform the following operation on these numbers:
Determine whether it is possible to have only one integer on the blackboard.
The input is given from Standard Input in the following format:
$N$ $A_1$ $A_2$ … $A_N$
If it is possible to have only one integer on the blackboard, print YES
. Otherwise, print NO
.
3 1 2 3
YES
It is possible to have only one integer on the blackboard, as follows:
5 1 2 3 4 5
NO