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:
//package Codeforce;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Spoilt {

	public static void main(String[] args) throws IOException {
		BufferedReader reader = new BufferedReader (new InputStreamReader(System.in));
		int len = Integer.parseInt(reader.readLine());
		String sequence = reader.readLine();
		String [] nums = sequence.split(" ");
		int start = 0;
		int end = 0;
		for (int i = 0; i < len; i++) {
			if (Integer.parseInt(nums[i]) != i+1)
			{
				start = i+1;
				break;
			}
		}
		
		for (int i = nums.length-1; i >= 0; i--) {
			if (Integer.parseInt(nums[i]) != i+1)
			{
				end = i+1;
				break;
			}
		}
		
		String result = start+" "+end;
		int index = start-1;
		int bound = end-1;
		while (index <= bound && index >= 0 && bound >= 0 )
		{
			if (Integer.parseInt(nums[index]) != end)
			{
				result = "0 0";
				break;
			}
			end--;
			index++;
		}
		
		System.out.println(result);
		reader.close();
	}
}