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.util.*;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.text.DecimalFormat;
import java.lang.Math;
import java.util.Iterator; 
public class b91{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n+1];
		for(int i = 1; i <= n; i++){
		    a[i] = sc.nextInt();
		}
		int count = 0;
		int x = 0;
		int y = 0;
		int flag = 0;
		if(a[1]==1 && a[n]!=n){
		    for(int i = 1; i <n; i++){
		        if(Math.abs(a[i]-a[i+1])!= 1 ){
		            count++;
		            x = i+1;
		        }
		    }
		    if(count==1){
		        System.out.println(x+" "+n);
		    }
		    else{
		        System.out.println(0+" "+0);
		    }
		}
		else if(a[1]!=1 && a[n]==n){
		    for(int i = 1; i <n; i++){
		        if(Math.abs(a[i]-a[i+1])!= 1){
		            count++;
		            x = i;
		        }
		    }
		    if(count==1){
		        System.out.println(1+" "+x);
		    }
		    else{
		        System.out.println(0+" "+0);
		    }
		}
		else if(a[1]==1 && a[n]==n){
		    for(int i = 1; i <n; i++){
		        if(Math.abs(a[i]-a[i+1]) != 1 && flag==0){
		            count++;
		            x = i+1;
		            flag = 1;
		        }
		        else if(Math.abs(a[i]-a[i+1]) != 1 && flag==1){
		            count++;
		            y = i;
		        }
		    }
		    if(count==2){
		        System.out.println(x+" "+y);
		    }
		    else{
		        System.out.println(0+" "+0);
		    }
		}
		else if(n==2 && a[2]==1){
		    System.out.println(1+" "+2);
		}
		else{
		    System.out.println(0+" "+0);
		}
	}	
}