import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] p = new int[n];
        int[] p2 = new int[n];
        int cnt =0;
        
        for(int i = 0;i<n;i++){
            p[i] = sc.nextInt();
        }



        for(int i = 0;i<n;i++){
           if(p[i]!=i+1){
               cnt++;
               //System.out.println(p[i]);
           }
        }

        //System.out.println(cnt);
        if(cnt==0 || cnt==2){
            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