import java.util.*; 

class Main{
public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
		int[] p=new int[n];
  		int d=0;
		for(int c=0;c<n;c++){
    		p[c]=sc.nextInt();
          	if(p[c]!=c+1){
            	d++;
            }
              
    	}
  		
  
 	if(d<=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