import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		ArrayList<Integer> p = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			p.add(sc.nextInt());
		}
		sc.close();

		int count = 0;
		for(int i = 0; i < n; i++) {
			if(p.get(i)!=i+1) {
				count++;
			}
		}

		if(count<=2) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}

	}

} import java.util.ArrayList; ArrayList java.util 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();
		ArrayList<Integer> p = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			p.add(sc.nextInt());
		}
		sc.close();

		int count = 0;
		for(int i = 0; i < n; i++) {
			if(p.get(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 = sc.nextInt();
		ArrayList<Integer> p = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			p.add(sc.nextInt());
		}
		sc.close();

		int count = 0;
		for(int i = 0; i < n; i++) {
			if(p.get(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 = sc.nextInt();
		ArrayList<Integer> p = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			p.add(sc.nextInt());
		}
		sc.close();

		int count = 0;
		for(int i = 0; i < n; i++) {
			if(p.get(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 = sc.nextInt(); n sc.nextInt() sc.nextInt sc ArrayList<Integer> p = new ArrayList<Integer>(); p new ArrayList<Integer>() for(int i = 0; i < n; i++) {
			p.add(sc.nextInt());
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			p.add(sc.nextInt());
		} {
			p.add(sc.nextInt());
		} p.add(sc.nextInt()) p.add p sc.nextInt() sc.nextInt sc sc.close() sc.close sc int count = 0; count 0 for(int i = 0; i < n; i++) {
			if(p.get(i)!=i+1) {
				count++;
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			if(p.get(i)!=i+1) {
				count++;
			}
		} {
			if(p.get(i)!=i+1) {
				count++;
			}
		} if(p.get(i)!=i+1) {
				count++;
			} p.get(i)!=i+1 p.get(i) p.get 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 = sc.nextInt();
		ArrayList<Integer> p = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			p.add(sc.nextInt());
		}
		sc.close();

		int count = 0;
		for(int i = 0; i < n; i++) {
			if(p.get(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 = sc.nextInt();
		ArrayList<Integer> p = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			p.add(sc.nextInt());
		}
		sc.close();

		int count = 0;
		for(int i = 0; i < n; i++) {
			if(p.get(i)!=i+1) {
				count++;
			}
		}

		if(count<=2) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}

	}

} Main
import java.util.ArrayList;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		ArrayList<Integer> p = new ArrayList<Integer>();
		for(int i = 0; i < n; i++) {
			p.add(sc.nextInt());
		}
		sc.close();

		int count = 0;
		for(int i = 0; i < n; i++) {
			if(p.get(i)!=i+1) {
				count++;
			}
		}

		if(count<=2) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}

	}

}
