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.BufferedReader;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Collection;
import java.util.Hashtable;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.StringTokenizer;

import javax.swing.JFileChooser;

public class Main {

    /**
     * @param args
     * @throws IOException 
     */
    
    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
  
        
        
         BufferedReader in = new BufferedReader(new InputStreamReader(
                 System.in));
          
         int cases = Integer.parseInt(in.readLine());
         String [] n = in.readLine().split(" ");
         int [] num = new int[n.length];
         boolean [] place = new boolean[n.length];
         for (int i = 0; i < num.length; i++) {
            num[i]=Integer.parseInt(n[i]);
            place[i]= (num[i]==i+1);
            try{
                if(!place[i-1]&&place[i]&&num[i-1]-num[i]==1)place[i]=false;
            }catch(Exception e ){
                
            }
        }
         
         int cor = 0;
         boolean foundCor = false;
         for (int i = 0; i < place.length; i++) {
            if(!place[i]&&!foundCor){
                cor++;
            }
            foundCor = ! place[i];
        }
         if(cor==1){
             boolean c = false;
             int lastnum = -1;
             int place1=-1,place2=-1;
             for (int i = 0; i < place.length; i++) {
                if (!place[i]){
                    if(i==0||lastnum==-1){lastnum = num[i];place1=i;}
                    else{
                        if(lastnum-1==num[i]){lastnum = num[i];place2=i;}
                        else{c=true;break;}
                    }
                }
            }
             if (c)System.out.println("0 0");
             else {System.out.println((place1+1)+" "+(place2+1));}
             
         }else{
             System.out.println("0 0");
         }
    }

    
    
   

}