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.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.BitSet;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.ListIterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.PriorityQueue;
import java.util.Queue;
public class A {

public static void main(String[] args) throws IOException  {
	  FastReader sc= new FastReader();
	  int n=sc.nextInt();
	  int a[]=new int[n+1];
	  for(int i=1;i<=n;i++) a[i]=sc.nextInt();
	  int p1=-1; int p2=-1;
	  for(int i=2;i<n;i++){
		  if(a[i]>a[i-1] && a[i]>a[i+1]) {
			  if(p1>0) { System.out.println("0 0"); return; }
			  else p1=i;
		  }
		  if(a[i]<a[i-1] && a[i]<a[i+1]){
			  if(p2>0) { System.out.println("0 0"); return; }
			  else p2=i;
		  }
	  }
	  if(p1>0 && p2>0){  if(p1>p2) { int t=p1; p1=p2; p2=t; }
	  }
	  else if(p1>0 || p2>0) {
		  if(p1>0) p2=n;
		  else if(p2>0) p1=1;
	  }else {
		  boolean ans1=true,ans2=true;
		  for(int i=1;i<n;i++) if(a[i]>a[i+1]) {ans1=false; break; }
		  if(ans1) { System.out.println("0 0"); return; }
		  for(int i=1;i<n;i++) if(a[i]<a[i+1]) { ans2=false; break; }
		  if(ans2) { System.out.println(1+" "+n); return; }
	  }
	 
	  for(int i=p1;i<=p1+(p2-p1)/2;i++){
		  int t=a[i];
		  a[i]=a[p2-i+p1];
		  a[p2-i+p1]=t;
	  }
	  	 for(int i=1;i<n;i++) if(a[i]>a[i+1]) {System.out.println("0 0"); return; }
	  	 	System.out.println(p1+" "+p2);
	  
}

	static long M=(long)Math.pow(10,9)+7;

	static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader(){
        		br = new BufferedReader(new InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt(){   return Integer.parseInt(next()); }
        
 
        long nextLong(){  return Long.parseLong(next()); }
        
           
        double nextDouble() {  return Double.parseDouble(next()); }
       
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
}