import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner scan = new java.util.Scanner(System.in);
        int n = scan.nextInt();
        int[] p = new int[n];
        int a = 0;
        for(int i = 0; i < n; i++){
            p[i] = scan.nextInt();
        }
        for(int i = 0; i < n; i++){
            if(p[i] - 1 != i){
                a++;
            }
        }
        if(a <= 2){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
} import java.util.*; util.* java public class Main{
    public static void main(String[] args){
        Scanner scan = new java.util.Scanner(System.in);
        int n = scan.nextInt();
        int[] p = new int[n];
        int a = 0;
        for(int i = 0; i < n; i++){
            p[i] = scan.nextInt();
        }
        for(int i = 0; i < n; i++){
            if(p[i] - 1 != i){
                a++;
            }
        }
        if(a <= 2){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
} Main public static void main(String[] args){
        Scanner scan = new java.util.Scanner(System.in);
        int n = scan.nextInt();
        int[] p = new int[n];
        int a = 0;
        for(int i = 0; i < n; i++){
            p[i] = scan.nextInt();
        }
        for(int i = 0; i < n; i++){
            if(p[i] - 1 != i){
                a++;
            }
        }
        if(a <= 2){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    } main {
        Scanner scan = new java.util.Scanner(System.in);
        int n = scan.nextInt();
        int[] p = new int[n];
        int a = 0;
        for(int i = 0; i < n; i++){
            p[i] = scan.nextInt();
        }
        for(int i = 0; i < n; i++){
            if(p[i] - 1 != i){
                a++;
            }
        }
        if(a <= 2){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    } Scanner scan = new java.util.Scanner(System.in); scan new java.util.Scanner(System.in) int n = scan.nextInt(); n scan.nextInt() scan.nextInt scan int[] p = new int[n]; p new int[n] n int a = 0; a 0 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 for(int i = 0; i < n; i++){
            if(p[i] - 1 != i){
                a++;
            }
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            if(p[i] - 1 != i){
                a++;
            }
        } {
            if(p[i] - 1 != i){
                a++;
            }
        } if(p[i] - 1 != i){
                a++;
            } p[i] - 1 != i p[i] - 1 p[i] p i 1 i {
                a++;
            } a++ a if(a <= 2){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        } a <= 2 a 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 scan = new java.util.Scanner(System.in);
        int n = scan.nextInt();
        int[] p = new int[n];
        int a = 0;
        for(int i = 0; i < n; i++){
            p[i] = scan.nextInt();
        }
        for(int i = 0; i < n; i++){
            if(p[i] - 1 != i){
                a++;
            }
        }
        if(a <= 2){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
} public class Main{
    public static void main(String[] args){
        Scanner scan = new java.util.Scanner(System.in);
        int n = scan.nextInt();
        int[] p = new int[n];
        int a = 0;
        for(int i = 0; i < n; i++){
            p[i] = scan.nextInt();
        }
        for(int i = 0; i < n; i++){
            if(p[i] - 1 != i){
                a++;
            }
        }
        if(a <= 2){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
} Main
import java.util.*;

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