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.PrintWriter;
import java.util.Scanner;

public class Solution {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int n = in.nextInt();
        int[] a = new int[n];

        for (int i = 0; i < a.length; i++)
            a[i] = in.nextInt();

        boolean ok = true;
        int i_start = 0;
        int i_finish = 0;

        for (int i = 1; i <= a.length; i++)
            if (a[i - 1] != i) {
                i_start = i;
                break;
            }

        if (i_start == 0)
            ok = false;
        else {
            i_finish = i_start;
            for (int i = a[i_start - 1]; i_finish <= n; i--) {
                if (a[i_finish - 1] != i)
                    break;
                i_finish++;
            }

            i_finish--;

            if (ok) {
                for (int i = i_finish + 1; i <= a.length; i++)
                    if (a[i - 1] != i) {
                        ok = false;
                        break;
                    }
            }
        }

        out.print(ok ? i_start + " " + i_finish : "0 0");
        out.close();
    }
}