import java.util.*;
  public class Main{
    public static void main(String[]args){
      Scanner sc = new Scanner(System.in);
      int N = sc.nextInt();
      int count = 0;
      int [] data = new int[50];

      for(int i = 0;i<N;i++){
        data[i] = sc.nextInt();
      }
      
      for(int k = 0;k<N;k++){
        if(data[k] != k+1){
          count++;
        }
      }
        if(count<=2){
          System.out.println("YES");
        }
        if(count>2){
          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