import java.util.Scanner;

public class Main {
	  public static void main(String[] args ) throws Exception {
		Scanner sc = new Scanner(System.in);
	
		int A = sc.nextInt();
		int[] array = new int[A];
		int count = 0;
		
		for (int i = 0;i < A; i++) {
			array[i] = sc.nextInt();
			if(array[i] != i+1) {
				count ++;
				if (count >= 3) {
					break;
				}
			}
		}
		if(count < 3) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz