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

} Main public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		int n = stdIn.nextInt();
		int [] p = new int[n];
		
		for(int i = 0; i < n; i++) {
			p[i] = stdIn.nextInt();
		}
		int cnt = 0;
		
		
		for(int i = 0; i < n; i++) {
			if(p[i]!= i+1) {
				cnt++;
			}
		}
		if(cnt <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
		
	} main {
		Scanner stdIn = new Scanner(System.in);
		int n = stdIn.nextInt();
		int [] p = new int[n];
		
		for(int i = 0; i < n; i++) {
			p[i] = stdIn.nextInt();
		}
		int cnt = 0;
		
		
		for(int i = 0; i < n; i++) {
			if(p[i]!= i+1) {
				cnt++;
			}
		}
		if(cnt <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
		
	} Scanner stdIn = new Scanner(System.in); stdIn new Scanner(System.in) int n = stdIn.nextInt(); n stdIn.nextInt() stdIn.nextInt stdIn int [] p = new int[n]; p new int[n] n for(int i = 0; i < n; i++) {
			p[i] = stdIn.nextInt();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			p[i] = stdIn.nextInt();
		} {
			p[i] = stdIn.nextInt();
		} p[i] = stdIn.nextInt() p[i] p i stdIn.nextInt() stdIn.nextInt stdIn int cnt = 0; cnt 0 for(int i = 0; i < n; i++) {
			if(p[i]!= i+1) {
				cnt++;
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			if(p[i]!= i+1) {
				cnt++;
			}
		} {
			if(p[i]!= i+1) {
				cnt++;
			}
		} if(p[i]!= i+1) {
				cnt++;
			} p[i]!= i+1 p[i] p i i+1 i 1 {
				cnt++;
			} cnt++ cnt if(cnt <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		} cnt <= 2 cnt 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 stdIn = new Scanner(System.in);
		int n = stdIn.nextInt();
		int [] p = new int[n];
		
		for(int i = 0; i < n; i++) {
			p[i] = stdIn.nextInt();
		}
		int cnt = 0;
		
		
		for(int i = 0; i < n; i++) {
			if(p[i]!= i+1) {
				cnt++;
			}
		}
		if(cnt <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
		
	}

} public class Main {
	
	public static void main(String[] args) {
		Scanner stdIn = new Scanner(System.in);
		int n = stdIn.nextInt();
		int [] p = new int[n];
		
		for(int i = 0; i < n; i++) {
			p[i] = stdIn.nextInt();
		}
		int cnt = 0;
		
		
		for(int i = 0; i < n; i++) {
			if(p[i]!= i+1) {
				cnt++;
			}
		}
		if(cnt <= 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 stdIn = new Scanner(System.in);
		int n = stdIn.nextInt();
		int [] p = new int[n];
		
		for(int i = 0; i < n; i++) {
			p[i] = stdIn.nextInt();
		}
		int cnt = 0;
		
		
		for(int i = 0; i < n; i++) {
			if(p[i]!= i+1) {
				cnt++;
			}
		}
		if(cnt <= 2) {
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
		
	}

}
