import java.util.Scanner;
 
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 cnt = 0;
    
    for (int i=0; i<N;i++){
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    }
    
    System.out.println("YES");
  }
} import java.util.Scanner; Scanner 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 cnt = 0;
    
    for (int i=0; i<N;i++){
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    }
    
    System.out.println("YES");
  }
} Main public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] p = new int[N];
    
    int cnt = 0;
    
    for (int i=0; i<N;i++){
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    }
    
    System.out.println("YES");
  } main {
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int[] p = new int[N];
    
    int cnt = 0;
    
    for (int i=0; i<N;i++){
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    }
    
    System.out.println("YES");
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[] p = new int[N]; p new int[N] N int cnt = 0; cnt 0 for (int i=0; i<N;i++){
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    } int i=0; int i=0; i 0 i<N i N i++ i++ i {
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    } {
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    } p[i] = sc.nextInt() p[i] p i sc.nextInt() sc.nextInt sc if (p[i] != (i+1)){
        cnt++;
      } p[i] != (i+1) p[i] p i (i+1) i 1 {
        cnt++;
      } cnt++ cnt if (cnt >= 3){
        System.out.println("NO");
        return;
      } cnt >= 3 cnt 3 {
        System.out.println("NO");
        return;
      } System.out.println("NO") System.out.println System.out System System.out "NO" return; System.out.println("YES") System.out.println System.out System System.out "YES" String[] args args 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 cnt = 0;
    
    for (int i=0; i<N;i++){
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    }
    
    System.out.println("YES");
  }
} 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 cnt = 0;
    
    for (int i=0; i<N;i++){
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    }
    
    System.out.println("YES");
  }
} Main
import java.util.Scanner;
 
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 cnt = 0;
    
    for (int i=0; i<N;i++){
      p[i] = sc.nextInt();
      if (p[i] != (i+1)){
        cnt++;
      }
      if (cnt >= 3){
        System.out.println("NO");
        return;
      }
    }
    
    System.out.println("YES");
  }
}