
import java.util.Scanner;


public class Main {
    public static void main(String[] args) {
        Scanner input = new Scanner (System.in);
         int n = input.nextInt();
    int[] array = new int[n];
    int count =0;
    for(int i=0;i<n;i++){
      array[i] = input.nextInt();
    }
    for(int j=0;j<n;j++){
      if(array [j] != j+1){
        count++;
      }
    }
    if(count == 2 || count == 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