P9461 [AtCoder] AtCoder Beginner Contest 135 - 0 or 1 Swap
入门
题目描述

We have a sequence p = {p_1,\ p_2,\ ...,\ p_N} which is a permutation of {1,\ 2,\ ...,\ N}.

You can perform the following operation at most once: choose integers i and $j (1 \leq i < j \leq N)$, and swap p_i and p_j. Note that you can also choose not to perform it.

Print YES if you can sort p in ascending order in this way, and NO otherwise.

Constraints

  • All values in input are integers.
  • $2 \leq N \leq 50$
  • p is a permutation of {1,\ 2,\ ...,\ N}.

Input

Input is given from Standard Input in the following format:

N
p_1 p_2 ... p_N

Output

Print YES if you can sort p in ascending order in the way stated in the problem statement, and NO otherwise.

Examples

Input

5
5 2 3 4 1

Output

YES

Input

5
2 4 3 5 1

Output

NO

Input

7
1 2 3 4 5 6 7

Output

YES

输入格式

见题面

输出格式

见题面

样例输入
5 2 4 3 5 1
样例输出
NO