import java.util.Scanner;
class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int li[] = new int[N];
    int count = 0;
    
    for(int i=0;i<N;i++){
      li[i] = sc.nextInt();
      if(li[i]!=i+1){
        count++;
      }
    }
    
    if(count==0 || count==2){
      System.out.println("YES");
    }else{
      System.out.println("NO");
    }
  }
}  import java.util.Scanner; Scanner java.util class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int li[] = new int[N];
    int count = 0;
    
    for(int i=0;i<N;i++){
      li[i] = sc.nextInt();
      if(li[i]!=i+1){
        count++;
      }
    }
    
    if(count==0 || count==2){
      System.out.println("YES");
    }else{
      System.out.println("NO");
    }
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int li[] = new int[N];
    int count = 0;
    
    for(int i=0;i<N;i++){
      li[i] = sc.nextInt();
      if(li[i]!=i+1){
        count++;
      }
    }
    
    if(count==0 || count==2){
      System.out.println("YES");
    }else{
      System.out.println("NO");
    }
  } main {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int li[] = new int[N];
    int count = 0;
    
    for(int i=0;i<N;i++){
      li[i] = sc.nextInt();
      if(li[i]!=i+1){
        count++;
      }
    }
    
    if(count==0 || count==2){
      System.out.println("YES");
    }else{
      System.out.println("NO");
    }
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int li[] = new int[N]; li new int[N] N int count = 0; count 0 for(int i=0;i<N;i++){
      li[i] = sc.nextInt();
      if(li[i]!=i+1){
        count++;
      }
    } int i=0; int i=0; i 0 i<N i N i++ i++ i {
      li[i] = sc.nextInt();
      if(li[i]!=i+1){
        count++;
      }
    } {
      li[i] = sc.nextInt();
      if(li[i]!=i+1){
        count++;
      }
    } li[i] = sc.nextInt() li[i] li i sc.nextInt() sc.nextInt sc if(li[i]!=i+1){
        count++;
      } li[i]!=i+1 li[i] li i i+1 i 1 {
        count++;
      } count++ count if(count==0 || count==2){
      System.out.println("YES");
    }else{
      System.out.println("NO");
    } count==0 || count==2 count==0 count 0 count==2 count 2 {
      System.out.println("YES");
    } System.out.println("YES") System.out.println System.out System System.out "YES" {
      System.out.println("NO");
    } System.out.println("NO") System.out.println System.out System System.out "NO" String[] args args
import java.util.Scanner;
class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int li[] = new int[N];
    int count = 0;
    
    for(int i=0;i<N;i++){
      li[i] = sc.nextInt();
      if(li[i]!=i+1){
        count++;
      }
    }
    
    if(count==0 || count==2){
      System.out.println("YES");
    }else{
      System.out.println("NO");
    }
  }
} 