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:
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author Saransh
 */
import java.io.*;
import java.util.*;
import java.math.*;
import java.lang.*;


public class Main {

    /**
     * @param args the command line arguments
     */
    
    public static void main(String[] args) {
        // TODO code application logic here
        try
        {
            Parserdoubt pd=new Parserdoubt(System.in);
            int t=pd.nextInt();
            int arr[]=new int[t+1];
            for(int i=1;i<=t;i++)
                arr[i]=pd.nextInt();
            int count=0;
            int anss=-1;
            int anse=-1;
            for(int i=1;i<=t;i++)
            {
                //System.out.println(arr[i]+" "+i);
                if(arr[i]!=i)
                {
                    count++;
                    if(anss==-1)
                    {
                        anss=arr[i];
                        anse=i;
                    }
                    
                    int tmp=i;
                    for(int k=arr[i];k>=i;k--)
                    {
                        if(arr[k]!=tmp)
                        {
                            System.out.println("0 0");
                            return;
                        }
                        tmp++;
                    }

                }
            }
            if(anss==-1){
                System.out.println(0+" "+0);return;}
            if((anss-anse)%2==0)
                count++;
            if(anss-anse+1==count)
            {
                System.out.println(anse+" "+anss);return;
            }
 else
            System.out.println(0+" "+0);
            

    
        }
        catch(Exception e)
        {}

    }
    
}


class Parserdoubt
    {
       final private int BUFFER_SIZE = 1 << 17;

       private DataInputStream din;
       private byte[] buffer;
       private int bufferPointer, bytesRead;

       public Parserdoubt(InputStream in)
       {
          din = new DataInputStream(in);
          buffer = new byte[BUFFER_SIZE];
          bufferPointer = bytesRead = 0;
       }
       public String nextString() throws Exception
       {
           StringBuffer sb=new StringBuffer("");
           byte c = read();
           while (c <= ' ') c = read();
           do
           {
               sb.append((char)c);
               c=read();
           }while(c>' ');
           return sb.toString();
       }
       public char nextChar() throws Exception
       {
           byte c=read();
           while(c<=' ') c= read();
           return (char)c;
       }
       public int nextInt() throws Exception
       {
          int ret = 0;
          byte c = read();
          while (c <= ' ') c = read();
          boolean neg = c == '-';
          if (neg) c = read();
          do
          {
              ret = ret * 10 + c - '0';
             c = read();
          } while (c > ' ');
          if (neg) return -ret;
          return ret;
       }
       public long nextLong() throws Exception
       {
          long ret = 0;
          byte c = read();
          while (c <= ' ') c = read();
          boolean neg = c == '-';
          if (neg) c = read();
          do
          {
              ret = ret * 10 + c - '0';
             c = read();
          } while (c > ' ');
          if (neg) return -ret;
          return ret;
       }
       private void fillBuffer() throws Exception
       {
          bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
          if (bytesRead == -1) buffer[0] = -1;
       }

       private byte read() throws Exception
       {
          if (bufferPointer == bytesRead) fillBuffer();
          return buffer[bufferPointer++];
       }
    }