import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		}
	}
} Main public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		}
	} main {
		try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		}
	} try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		} {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		} Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int[] p = new int[n]; p new int[n] n for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			} int i = 0 ; int i = 0 ; i 0 i < n i n i++ i++ i {
				p[i] = sc.nextInt();
			} {
				p[i] = sc.nextInt();
			} p[i] = sc.nextInt() p[i] p i sc.nextInt() sc.nextInt sc int count = 0; count 0 for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			} int i = 0 ; int i = 0 ; i 0 i < n i n i++ i++ i {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			} {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			} if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				} (i+1) == p[i] (i+1) i 1 p[i] p i {
					//OK
				} {
					count++;
				} count++ count if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			} count < 3 count 3 {
				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 public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		}
	}
} public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		}
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args){
		try(Scanner sc = new Scanner(System.in)) {

			int n = sc.nextInt();
			int[] p = new int[n];
			
			for(int i = 0 ; i < n ; i++ ) {
				p[i] = sc.nextInt();
			}
			
			int count = 0;
			for(int i = 0 ; i < n ; i++ ) {
				if ( (i+1) == p[i] ) {
					//OK
				}
				else {
					count++;
				}
			}
			
			if ( count < 3 ) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			
		}
	}
}