import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int cnt = 0;
		
		for (int i = 0; i<n; i++) {
			if (sc.nextInt() != i+1) {
				cnt += 1;
			}
			if (cnt > 2) {
				break;
			}
		}

		if (cnt > 2) {
			System.out.println("NO");
		} else {
			System.out.println("YES");
		}
}}
/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