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;

/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author KHALED
 */
public class SpoiltPermutation {
    public static boolean isSorted(int[]arr)
    {
        if(arr.length==1)
            return true;
        for (int i = 0; i < arr.length-1; i++) 
        {
            if(arr[i+1]<arr[i])
                return false;
        }
        return true;
    }
    public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);
        int n=scan.nextInt();
        int[]arr=new int[n];
        for (int i = 0; i < n; i++) 
        {
            arr[i]=scan.nextInt();
        }
        if(isSorted(arr)||n==1)
        {
            System.out.println(0+" "+0);
            return;
        }
        int start=0,end=0;
        int index=1;
        boolean started=false;
        while(index<n)
        {
            if(arr[index]<arr[index-1]&&started==false)
            {
                start=index-1;
                started=true;
            }
            if(arr[index]<arr[index-1]&&started==true)
            {
                end=index;
            }
            if(arr[index]>arr[index-1]&&started==true)
            {
                break;
            }
            index++;
        }
        if(end-start==1)
        {
            int temp=arr[start];
            arr[start]=arr[end];
            arr[end]=temp;
        }
        else
        {
            int co=0;
            for (int i = start; i <= start+(end-start)/2; i++) 
            {
                int temp=arr[i];
                arr[i]=arr[end-co];
                arr[end-co]=temp;
                co++;
            }
        }
        start++;
        end++;
        if(isSorted(arr))
            System.out.println(start+" "+end);
        else
            System.out.println(0+" "+0);
    }
}