import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int result = 0;
        for (int i = 1; i <= a; i++) {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        }

        if (result == 0 || result == 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 sc = new Scanner(System.in);
        int a = sc.nextInt();
        int result = 0;
        for (int i = 1; i <= a; i++) {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        }

        if (result == 0 || result == 2) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int result = 0;
        for (int i = 1; i <= a; i++) {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        }

        if (result == 0 || result == 2) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int result = 0;
        for (int i = 1; i <= a; i++) {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        }

        if (result == 0 || result == 2) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int result = 0; result 0 for (int i = 1; i <= a; i++) {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        } int i = 1; int i = 1; i 1 i <= a i a i++ i++ i {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        } {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        } int tmp = sc.nextInt(); tmp sc.nextInt() sc.nextInt sc if (tmp != i) result++; tmp != i tmp i result++ result if (result == 0 || result == 2) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        } result == 0 || result == 2 result == 0 result 0 result == 2 result 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 a = sc.nextInt();
        int result = 0;
        for (int i = 1; i <= a; i++) {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        }

        if (result == 0 || result == 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 a = sc.nextInt();
        int result = 0;
        for (int i = 1; i <= a; i++) {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        }

        if (result == 0 || result == 2) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int result = 0;
        for (int i = 1; i <= a; i++) {
            int tmp = sc.nextInt();
            if (tmp != i) result++;
        }

        if (result == 0 || result == 2) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
}
