import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        int[] p = new int[N];
        for (int i = 0; i < N; i++) {
            p[i] = Integer.parseInt(sc.next());
        }

        int ctn = 0;
        for (int i = 0; i < N; i++) {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        }
        if (ctn > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        int[] p = new int[N];
        for (int i = 0; i < N; i++) {
            p[i] = Integer.parseInt(sc.next());
        }

        int ctn = 0;
        for (int i = 0; i < N; i++) {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        }
        if (ctn > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        int[] p = new int[N];
        for (int i = 0; i < N; i++) {
            p[i] = Integer.parseInt(sc.next());
        }

        int ctn = 0;
        for (int i = 0; i < N; i++) {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        }
        if (ctn > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        int[] p = new int[N];
        for (int i = 0; i < N; i++) {
            p[i] = Integer.parseInt(sc.next());
        }

        int ctn = 0;
        for (int i = 0; i < N; i++) {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        }
        if (ctn > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = Integer.parseInt(sc.next()); N Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int[] p = new int[N]; p new int[N] N for (int i = 0; i < N; i++) {
            p[i] = Integer.parseInt(sc.next());
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            p[i] = Integer.parseInt(sc.next());
        } {
            p[i] = Integer.parseInt(sc.next());
        } p[i] = Integer.parseInt(sc.next()) p[i] p i Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int ctn = 0; ctn 0 for (int i = 0; i < N; i++) {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        } {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        } if (p[i] == i + 1) {
                continue;
            } p[i] == i + 1 p[i] p i i + 1 i 1 {
                continue;
            } continue; ctn++ ctn if (ctn > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        } ctn > 2 ctn 2 {
            System.out.println("NO");
        } System.out.println("NO") System.out.println System.out System System.out "NO" {
            System.out.println("YES");
        } System.out.println("YES") System.out.println System.out System System.out "YES" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        int[] p = new int[N];
        for (int i = 0; i < N; i++) {
            p[i] = Integer.parseInt(sc.next());
        }

        int ctn = 0;
        for (int i = 0; i < N; i++) {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        }
        if (ctn > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        int[] p = new int[N];
        for (int i = 0; i < N; i++) {
            p[i] = Integer.parseInt(sc.next());
        }

        int ctn = 0;
        for (int i = 0; i < N; i++) {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        }
        if (ctn > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = Integer.parseInt(sc.next());
        int[] p = new int[N];
        for (int i = 0; i < N; i++) {
            p[i] = Integer.parseInt(sc.next());
        }

        int ctn = 0;
        for (int i = 0; i < N; i++) {
            if (p[i] == i + 1) {
                continue;
            }
            ctn++;
        }
        if (ctn > 2) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    }
}
