import java.util.*;
public class Main{
	public static void main(String[] args){
      Scanner sc = new Scanner(System.in);
      int n = sc.nextInt();
      int[] array = new int[n];
      for(int i = 0;i < array.length;i++){
      	array[i] = sc.nextInt();
      }
      
      int count1 = 0;
      for(int i = 0;i < array.length;i++){
      	if(array[i] != i+1) count1++;
      }
      
      if(count1 == 0 || count1 == 2 ) System.out.print("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