import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		int[] P = new int[N];
		for(int i = 0; i < N; i++) {
			P[i] = Integer.parseInt(sc.next());
		}
		sc.close();
		
		int count = 0;
		for(int i = 0; i < N; i++) {
			if(P[i] != i + 1) {
				count++;
			}
		}
		if(count <= 2) {
			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) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		int[] P = new int[N];
		for(int i = 0; i < N; i++) {
			P[i] = Integer.parseInt(sc.next());
		}
		sc.close();
		
		int count = 0;
		for(int i = 0; i < N; i++) {
			if(P[i] != i + 1) {
				count++;
			}
		}
		if(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 = Integer.parseInt(sc.next());
		int[] P = new int[N];
		for(int i = 0; i < N; i++) {
			P[i] = Integer.parseInt(sc.next());
		}
		sc.close();
		
		int count = 0;
		for(int i = 0; i < N; i++) {
			if(P[i] != i + 1) {
				count++;
			}
		}
		if(count <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}

	} main {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		int[] P = new int[N];
		for(int i = 0; i < N; i++) {
			P[i] = Integer.parseInt(sc.next());
		}
		sc.close();
		
		int count = 0;
		for(int i = 0; i < N; i++) {
			if(P[i] != i + 1) {
				count++;
			}
		}
		if(count <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = Integer.parseInt(sc.next()); N Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int[] P = new int[N]; P new int[N] N for(int i = 0; i < N; i++) {
			P[i] = Integer.parseInt(sc.next());
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			P[i] = Integer.parseInt(sc.next());
		} {
			P[i] = Integer.parseInt(sc.next());
		} P[i] = Integer.parseInt(sc.next()) P[i] P i Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc sc.close() sc.close sc int count = 0; count 0 for(int i = 0; i < N; i++) {
			if(P[i] != i + 1) {
				count++;
			}
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			if(P[i] != i + 1) {
				count++;
			}
		} {
			if(P[i] != i + 1) {
				count++;
			}
		} if(P[i] != i + 1) {
				count++;
			} P[i] != i + 1 P[i] P i i + 1 i 1 {
				count++;
			} count++ count if(count <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		} 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 public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		int[] P = new int[N];
		for(int i = 0; i < N; i++) {
			P[i] = Integer.parseInt(sc.next());
		}
		sc.close();
		
		int count = 0;
		for(int i = 0; i < N; i++) {
			if(P[i] != i + 1) {
				count++;
			}
		}
		if(count <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}

	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		int[] P = new int[N];
		for(int i = 0; i < N; i++) {
			P[i] = Integer.parseInt(sc.next());
		}
		sc.close();
		
		int count = 0;
		for(int i = 0; i < N; i++) {
			if(P[i] != i + 1) {
				count++;
			}
		}
		if(count <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}

	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		int[] P = new int[N];
		for(int i = 0; i < N; i++) {
			P[i] = Integer.parseInt(sc.next());
		}
		sc.close();
		
		int count = 0;
		for(int i = 0; i < N; i++) {
			if(P[i] != i + 1) {
				count++;
			}
		}
		if(count <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}

	}

}