import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            int n = Integer.parseInt(in.next());
            int p[] = new int[n];
            for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            }

            int ans = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            }

            // 出力
            if (ans <= 2) out.println("YES");
            else out.println("NO");

        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            int n = Integer.parseInt(in.next());
            int p[] = new int[n];
            for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            }

            int ans = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            }

            // 出力
            if (ans <= 2) out.println("YES");
            else out.println("NO");

        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) B solver = new B(); solver new B() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            int n = Integer.parseInt(in.next());
            int p[] = new int[n];
            for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            }

            int ans = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            }

            // 出力
            if (ans <= 2) out.println("YES");
            else out.println("NO");

        }

    } B public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            int n = Integer.parseInt(in.next());
            int p[] = new int[n];
            for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            }

            int ans = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            }

            // 出力
            if (ans <= 2) out.println("YES");
            else out.println("NO");

        } solve {
            // 入力
            int n = Integer.parseInt(in.next());
            int p[] = new int[n];
            for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            }

            int ans = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            }

            // 出力
            if (ans <= 2) out.println("YES");
            else out.println("NO");

        } int n = Integer.parseInt(in.next()); n Integer.parseInt(in.next()) Integer.parseInt Integer in.next() in.next in int p[] = new int[n]; p new int[n] n for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                p[i] = Integer.parseInt(in.next());
            } {
                p[i] = Integer.parseInt(in.next());
            } p[i] = Integer.parseInt(in.next()) p[i] p i Integer.parseInt(in.next()) Integer.parseInt Integer in.next() in.next in int ans = 0; ans 0 for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                if (p[i] != i + 1) ans++;
            } {
                if (p[i] != i + 1) ans++;
            } if (p[i] != i + 1) ans++; p[i] != i + 1 p[i] p i i + 1 i 1 ans++ ans if (ans <= 2) out.println("YES");
            else out.println("NO"); ans <= 2 ans 2 out.println("YES") out.println out "YES" out.println("NO") out.println out "NO" int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            int n = Integer.parseInt(in.next());
            int p[] = new int[n];
            for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            }

            int ans = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            }

            // 出力
            if (ans <= 2) out.println("YES");
            else out.println("NO");

        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            int n = Integer.parseInt(in.next());
            int p[] = new int[n];
            for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            }

            int ans = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            }

            // 出力
            if (ans <= 2) out.println("YES");
            else out.println("NO");

        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            int n = Integer.parseInt(in.next());
            int p[] = new int[n];
            for (int i = 0; i < n; i++) {
                p[i] = Integer.parseInt(in.next());
            }

            int ans = 0;
            for (int i = 0; i < n; i++) {
                if (p[i] != i + 1) ans++;
            }

            // 出力
            if (ans <= 2) out.println("YES");
            else out.println("NO");

        }

    }
}

