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.lang.*;
import java.util.*;
import java.util.ArrayList;
import java.text.DecimalFormat;  





public class Main {
	
	
	static ArrayList<Integer> l[];
	static int mark[]=new int [100000];
	static int ans[]=new int [100000];
	
	public static int min(int x,int y)
	{
		return x>y?y:x;
	}
	public static int max(int x,int y)
	{
		return x>y?x:y;
	}
    public static void cout(String s)
    {
        System.out.println(s);
        
    }
    public static void main(String[] args) {
    	
    
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) {
        	
        	int n=in.nextInt();
        	int a[]=new int[1100];
        	int i,j,k;
        	for(i=1;i<=n;i++)
        		a[i]=in.nextInt();
        	
        	boolean ff=false;
        	for(i=1;i<=n;i++)
        	{
        		if(a[i]!=i)
        		{
        			for(j=a[i]+1;j<=n;j++)
        			{
        				if(a[j]!=j)
        					break;
        			}
        			if(j<=n)
        				break;
        			for(j=i+1;j<=a[i];j++)
        			{
        				if(a[j]!=a[j-1]-1)
        					break;
        			}
        			if(j<=a[i])
        				break;
        			ff=true;
        			System.out.println(i+" "+a[i]);
        			break;
        			
        		}
        		
        	
        	}
        	if(!ff)
        		System.out.println("0 0");
        	
        	
        	
        	
        
        
        }
    }
 
    
}