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.Scanner;

/**
 *
 * @author epiZend
 */
public class Spoilt {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int last = 0;
        int begin = 0, end = 0;
        boolean interval = false;
        for (int i = 1; i <= n; i++) {
            int coin = sc.nextInt();
            if (interval) {

                if (coin != last - 1) {
                    if (i == coin) {
                        end = i - 1;
                        interval = false;
                    } else {
                        System.out.println("0 0");
                        return;
                    }
                }
            } else if (coin != i) {
                if (end != 0) {
                    System.out.println("0 0");
                    return;
                }
                begin = i;
                interval = true;
            }
            last = coin;
        }
        if(end == 0 && begin != 0){
            end = n;
        }
        System.out.println(begin + " " + end);
    }
}