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 SpoiltPermutation {
	public static void main(String[]args)throws Throwable{
		BufferedReader bf=new BufferedReader(new InputStreamReader(System.in));
		int n=Integer.parseInt(bf.readLine());
		String s=bf.readLine();
		String[]sa=s.split(" ");
		int[]a=new int[n];
		for(int i=0;i<n;i++){
			a[i]=Integer.parseInt(sa[i]);
		}
		int start=-1,end=-1;
		for(int i=0;i<n;i++){
			if(start==-1 && i<n-1 && a[i]>a[i+1])
				start=i;
			if(i>0 && a[i]<a[i-1])
				end=i;
		}
		if(start>-1 && end>-1)
			for(int i=start;i<=((start+end)>>1);i++){
				int tmp=a[i];
				a[i]=a[start+end-i];
				a[start+end-i]=tmp;
			}
		if(sorted(a) && start!=-1 && end!=-1)
			System.out.println((start+1)+" "+(end+1));
		else
			System.out.println("0 0");
	}
	
	public static boolean sorted(int[]a){
		for(int i=1;i<a.length;i++)
			if(a[i]<a[i-1])
				return false;
		return true;
	}
}