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