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];
		for(int i = 0; i < N; i++) {
			p[i] = sc.nextInt();
		}
		sc.close();
		int r = 0;
		for(int i = 0; i < N; i++) {
			if(p[i] != i + 1) r++;
		}
		System.out.println(r <= 2 ? "YES" : "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[] p = new int[N];
		for(int i = 0; i < N; i++) {
			p[i] = sc.nextInt();
		}
		sc.close();
		int r = 0;
		for(int i = 0; i < N; i++) {
			if(p[i] != i + 1) r++;
		}
		System.out.println(r <= 2 ? "YES" : "NO");
	}
} Main public static void main(String[] args) {
		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();
		}
		sc.close();
		int r = 0;
		for(int i = 0; i < N; i++) {
			if(p[i] != i + 1) r++;
		}
		System.out.println(r <= 2 ? "YES" : "NO");
	} main {
		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();
		}
		sc.close();
		int r = 0;
		for(int i = 0; i < N; i++) {
			if(p[i] != i + 1) r++;
		}
		System.out.println(r <= 2 ? "YES" : "NO");
	} 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 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 sc.close() sc.close sc int r = 0; r 0 for(int i = 0; i < N; i++) {
			if(p[i] != i + 1) r++;
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			if(p[i] != i + 1) r++;
		} {
			if(p[i] != i + 1) r++;
		} if(p[i] != i + 1) r++; p[i] != i + 1 p[i] p i i + 1 i 1 r++ r System.out.println(r <= 2 ? "YES" : "NO") System.out.println System.out System System.out r <= 2 ? "YES" : "NO" r <= 2 r 2 "YES" "NO" 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];
		for(int i = 0; i < N; i++) {
			p[i] = sc.nextInt();
		}
		sc.close();
		int r = 0;
		for(int i = 0; i < N; i++) {
			if(p[i] != i + 1) r++;
		}
		System.out.println(r <= 2 ? "YES" : "NO");
	}
} public class Main {
	public static void main(String[] args) {
		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();
		}
		sc.close();
		int r = 0;
		for(int i = 0; i < N; i++) {
			if(p[i] != i + 1) r++;
		}
		System.out.println(r <= 2 ? "YES" : "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[] p = new int[N];
		for(int i = 0; i < N; i++) {
			p[i] = sc.nextInt();
		}
		sc.close();
		int r = 0;
		for(int i = 0; i < N; i++) {
			if(p[i] != i + 1) r++;
		}
		System.out.println(r <= 2 ? "YES" : "NO");
	}
}
