Problem:
Score : 200 points

Problem Statement

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.

Sample Input 1

5
5 2 3 4 1

Sample Output 1

YES

You can sort p in ascending order by swapping p_1 and p_5.

Sample Input 2

5
2 4 3 5 1

Sample Output 2

NO

In this case, swapping any two elements does not sort p in ascending order.

Sample Input 3

7
1 2 3 4 5 6 7

Sample Output 3

YES

p is already sorted in ascending order, so no operation is needed.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
public class Main {
static int A= 0;


	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		A=sc.nextInt();
		int T=0;
		int S=0;
		int count=0;
		int B =0;
		int C= 0;
		int data []=new int[A];
		
		for(int i=0;i<A;i++) {
		data[i] =sc.nextInt();	
		C = data[i];
		if(B > C) {
			
			if(T==0) {
				
				T=i-1;
				
			}else {
				
				S=i;
			}

			count++;
			if(count>2) break;
		}
		B= data[i];
		
		}
		if(count>2) {
			System.out.println("NO");
		}else {
			int temp=data[T];
			data[T]=data[S];
			data[S]=temp;
			for(int i=0;i<A;i++) {
				if(i==A-1) {
					System.out.println("YES");

				}else if( data[i]>data[i+1]) {
					System.out.println("NO");
					break;
				}
		}
		
		

	}
}
}