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.*;
import java.util.*;

public class Main {
//	static Scanner in; static int next() throws Exception {return in.nextInt();}
	static PrintWriter out;
	static StreamTokenizer in; static int next() throws Exception {in.nextToken(); return (int) in.nval;}

	public static void main(String[] args) throws Exception {
//		in = new Scanner(System.in);
		out = new PrintWriter(System.out);
		in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));

		int n = next();
		
		int[] x = new int[n];
		for (int i = 0; i < n; i++) x[i] = next() - 1;
		int a = 0;
		while (a < n && x[a] == a) a++;
		int b = n - 1;
		while (b >= 0 && x[b] == b) b--;
		boolean ok = a != n;
		for (int i = a; i <= b; i++) ok &= x[b + a - i] == i;
		if (!ok) a = b = -1;
		out.println(++a + " " + ++b);

		out.close();          
	}
}