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:
import java.awt.Point;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.MathContext;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Deque;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeSet;

import javax.swing.text.StyledEditorKit.ItalicAction;

import static java.lang.Double.*;
import static java.lang.Integer.*;
import static java.math.BigInteger.*;
import static java.lang.Math.*;
import static java.util.Arrays.*;

public class Main implements Runnable {
	
	private void solve() throws IOException {
//		long start = System.currentTimeMillis();
		readData();
		processing();
	}
	
	private void processing() {
		for (int i = 0; i < n; ++i) {
			if (a[i] != i) {
				int l = i;
				int r = a[i];
				if (check(l, r) && correct(r+1, n-1)) {
					print(l+1);
					print(" ");
					print(r+1);
					return;
				}
				else {
					print("0 0");
					return;
				}
			}
		}
		println("0 0");
	}	
	
	private boolean check(int l, int r) {
		for (int i = l; i <= r; ++i) {
			if (a[i] != r + l - i) {
				return false;
			}
		}
		return true;
	}
	
	private boolean correct(int l, int r) {
		for (int i = l; i <= r; ++i) {
			if (a[i] != i) {
				return false;
			}
		}
		return true;
	}
	
	private void readData() throws IOException {
		n = nextInt();
		a = new int[n];
		for (int i = 0; i < n; ++i) {
			a[i] = nextInt()-1;
		}
	}
	
	private int n;
	private int[] a;
	
	public static void main(String[] args) throws InterruptedException {
		new Thread(null, new Runnable() {
			public void run() {
				new Main().run();
			}
		}, "1", 1 << 24).start();
	}

	// @Override
	public void run() {
		try {
			boolean onlineJudge = System.getProperty("ONLINE_JUDGE") != null;
			reader = onlineJudge ? new BufferedReader(new InputStreamReader(
					System.in)) : new BufferedReader(
					new FileReader("input.txt"));
			writer = onlineJudge ? new PrintWriter(new BufferedWriter(
					new OutputStreamWriter(System.out))) : new PrintWriter(
					new BufferedWriter(new FileWriter("output.txt")));
			Locale.setDefault(Locale.US);
			tokenizer = null;
			solve();
			writer.flush();
		} catch (Exception error) {
			error.printStackTrace();
			System.exit(1);
		}
	}

	private BufferedReader reader;
	private PrintWriter writer;
	private StringTokenizer tokenizer;

	private void println() {
		writer.println();
	}
	
	private void print(long value) {
		writer.print(value);
	}
	
	private void println(long value) {
		writer.println(value);
	}
	
	private void print(char ch) {
		writer.print(ch);
	}

	private void println(String s) {
		writer.println(s);
	}

	private void print(String s) {
		writer.print(s);
	}
	
	private void print(int value) {
		writer.print(value);
	}
	
	private void println(int value) {
		writer.println(value);
	}

	private void printf(String f, double d) {
		writer.printf(f, d);
	}

	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 (tokenizer == null || !tokenizer.hasMoreTokens()) {
			tokenizer = new StringTokenizer(reader.readLine());
		}
		return tokenizer.nextToken();
	}
}