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.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

public class A1 {

	static InputStreamReader inp = new InputStreamReader(System.in);
	static BufferedReader in = new BufferedReader(inp);
	static boolean test = false;
	static PrintWriter writer = new PrintWriter(System.out);

	static String testDataFile = "testdata.txt";
	BufferedReader reader = null;

	public A1() throws Throwable {
		if (test) {
			reader = new BufferedReader(new FileReader(new File(testDataFile)));
		}
	}

	private void solve() throws Throwable, IOException {
		
		int n = in();
		int[] vals = ints();
		
		int firstPos =  -1;
		int firstVal =  -1;
		
		for (int i = 0; i < vals.length; i++) {
			if(vals[i] != i + 1){
				if(firstPos == -1){
					
					firstPos = i;
					firstVal = vals[i];
					
				} else { 
					int expected = firstVal - (i - firstPos);
					if(expected != vals[i]){
						System.out.println("0 0");
						return;
					}
				}
			}
		}
		
		if(firstPos == -1){
			System.out.println("0 0");
			return;
		}
		System.out.println((firstPos + 1) +  " " + (vals[firstPos]));
		
	}

	public String ln() throws IOException {
		if (test)
			return reader.readLine();
		else
			return in.readLine();
	}

	/**
	 * read a single integer should be a full line
	 */
	private int in() throws NumberFormatException, IOException {
		return Integer.valueOf(ln());
	}

	/**
	 * Read one line and split contents to an int array
	 */
	private int[] ints() throws Exception {
		String[] split = ln().split(" ");
		int[] list = new int[split.length];
		for (int i = 0; i < list.length; i++) {
			list[i] = Integer.parseInt(split[i]);
		}
		return list;
	}

	/**
	 * Entry point
	 */
	public static void main(String[] args) throws Throwable {
		new A1().solve();
	}
}