import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int N = sc.nextInt();//データ数
		int p[] = new int[N]; //配列数を決定
		int count = 0;
		for(int i = 0; i<N; i++) {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		}
		//System.out.println(count); //count数を確認
		if(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();//データ数
		int p[] = new int[N]; //配列数を決定
		int count = 0;
		for(int i = 0; i<N; i++) {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		}
		//System.out.println(count); //count数を確認
		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();//データ数
		int p[] = new int[N]; //配列数を決定
		int count = 0;
		for(int i = 0; i<N; i++) {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		}
		//System.out.println(count); //count数を確認
		if(count <= 2){
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
	} main {
		Scanner sc = new Scanner(System.in);
		
		int N = sc.nextInt();//データ数
		int p[] = new int[N]; //配列数を決定
		int count = 0;
		for(int i = 0; i<N; i++) {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		}
		//System.out.println(count); //count数を確認
		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 int p[] = new int[N]; p new int[N] N int count = 0; count 0 for(int i = 0; i<N; i++) {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		} int i = 0; int i = 0; i 0 i<N i N i++ i++ i {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		} {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		} p[i] = sc.nextInt() p[i] p i sc.nextInt() sc.nextInt sc if(p[i] != i+1) {
				count++;
			} p[i] != i+1 p[i] 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();//データ数
		int p[] = new int[N]; //配列数を決定
		int count = 0;
		for(int i = 0; i<N; i++) {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		}
		//System.out.println(count); //count数を確認
		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();//データ数
		int p[] = new int[N]; //配列数を決定
		int count = 0;
		for(int i = 0; i<N; i++) {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		}
		//System.out.println(count); //count数を確認
		if(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();//データ数
		int p[] = new int[N]; //配列数を決定
		int count = 0;
		for(int i = 0; i<N; i++) {
			p[i] = sc.nextInt(); //配列の中身を挿入
			//System.out.println(d[i]);//配列の中身を確認
			if(p[i] != i+1) {
				count++;
			}
		}
		//System.out.println(count); //count数を確認
		if(count <= 2){
			System.out.println("YES");
		}else {
			System.out.println("NO");
		}
	}
	
}
