import java.util.Scanner;

public class Main {

    public static void main(String args[] ) throws Exception {


        Scanner s = new Scanner(System.in);


        int N = s.nextInt();    // Reading input from STDIN

        int i=1;

        String result = "YES";
        int count = 0;
        while(i<=N){
            int p = s.nextInt();
            count += i!=p?1:0;

            if(count>2){
                result = "NO";
                break;
            }
            i++;
        }
        System.out.println(result);

    }
}

/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