import java.util.Scanner;

public class Main {

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

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