Problem: Vasya collects coins: he has exactly one coin for every year from 1 to n. Naturally, Vasya keeps all the coins in his collection in the order in which they were released. Once Vasya's younger brother made a change — he took all the coins whose release year dated from l to r inclusively and put them in the reverse order. That is, he took a certain segment [l, r] and reversed it. At that the segment's endpoints did not coincide. For example, if n = 8, then initially Vasya's coins were kept in the order 1 2 3 4 5 6 7 8. If Vasya's younger brother chose the segment [2, 6], then after the reversal the coin order will change to 1 6 5 4 3 2 7 8. Vasya suspects that someone else could have spoilt the permutation after his brother. Help him to find that out. Check if the given permutation can be obtained from the permutation 1 2 ... n using exactly one segment reversal. If it is possible, find the segment itself.

Input

The first line contains an integer n (1 ≤ n ≤ 1000) which is the number of coins in Vasya's collection. The second line contains space-separated n integers which are the spoilt sequence of coins. It is guaranteed that the given sequence is a permutation, i.e. it contains only integers from 1 to n, and every number is used exactly 1 time.

Output

If it is impossible to obtain the given permutation from the original one in exactly one action, print 0 0. Otherwise, print two numbers l r (1 ≤ l < r ≤ n) which are the endpoints of the segment that needs to be reversed to obtain from permutation 1 2 ... n the given one.

Examples

Input

8
1 6 5 4 3 2 7 8


Output

2 6


Input

4
2 3 4 1


Output

0 0


Input

4
1 2 3 4


Output

0 0

Solution (in JAVA):

Solution:
/**
 * Created by IntelliJ IDEA.
 * User: Taras_Brzezinsky
 * Date: 9/13/11
 * Time: 5:33 PM
 * To change this template use File | Settings | File Templates.
 */

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.IOException;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;

public class TaskB extends Thread {
    public TaskB() {
        this.input = new BufferedReader(new InputStreamReader(System.in));
        this.output = new PrintWriter(System.out);
        this.setPriority(Thread.MAX_PRIORITY);
    }




    private void solve() throws Throwable {
        int n = nextInt();
        int[] what = new int[n];
        for (int i = 0; i < n; ++i) {
            what[i] = nextInt() - 1;
        }
        for (int l = 0; l < n; ++l) {
            if (what[l] != l) {
                int r = l + 1;
                while (r < n && what[r - 1] == what[r] + 1) {
                    ++r;
                }
                --r;
                int L = l, R = r;
                while (l < r) {
                    int t = what[l];
                    what[l] = what[r];
                    what[r] = t;
                    ++l;
                    --r;
                }
                for (int i = 0; i < n; ++i) {
                    if (what[i] != i) {
                        output.println("0 0");
                        return;
                    }
                }
                output.println((L + 1) + " " + (R + 1));
                return;
            }
        }
        output.println("0 0");

    }


    public void run() {
        try {
            solve();
        } catch (Throwable e) {
            System.err.println(e.getMessage());
            e.printStackTrace();
            System.exit(666);
        } finally {
            output.flush();
            output.close();
        }
    }

    public static void main(String[] args) {
        new TaskB().start();
    }

    private int nextInt() throws IOException {
        return Integer.parseInt(nextToken());
    }

    private long nextLong() throws IOException {
        return Long.parseLong(nextToken());
    }

    private double nextDouble() throws IOException {
        return Double.parseDouble(nextToken());
    }

    private String nextToken() throws IOException {
        while (tokens == null || !tokens.hasMoreTokens()) {
            tokens = new StringTokenizer(input.readLine());
        }
        return tokens.nextToken();
    }

    private BufferedReader input;
    private PrintWriter output;
    private StringTokenizer tokens = null;
}