
import java.util.Scanner;



public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int con = 0;
		for (int i = 1; i < N+1; i++) {

			if (i != sc.nextInt()) {
				con++;
			}
		}

		if (con == 2 || con==0) {
			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