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.util.ArrayList;
import java.util.Scanner;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author jtim
 */
public class SpolitPermutation {

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int n = s.nextInt();
        int nums[] = new int[n];
        for (int i = 0; i < n; i++) {
            nums[i] = s.nextInt();
        }
        for (int left = 0; left < n - 1; left++) {
            for (int right = left + 1; right < n; right++) {
                if (check(nums, left, right)) {
                    System.out.println((left + 1) + " " + (right + 1));
                    return;
                }
            }
        }
        System.out.println("0 0");
    }

    private static boolean check(int[] nums, int left, int right) {
        for (int i = 0; i < left; i++) {
            if (nums[i] != i + 1) {
                return false;
            }
        }
        for (int i = right + 1; i < nums.length; i++) {
            if (nums[i] != i + 1) {
                return false;
            }
        }
        int cur = right + 1;
        for (int i = left; i <= right; i++) {
            if (nums[i] != cur) {
                return false;
            }
            cur--;
        }
        return true;
    }
}