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.util.Scanner;
public class SpoiltPermutation{

    public static void main(String[] args){

	Scanner sc = new Scanner(System.in);
	int n = sc.nextInt();
	int l = 0;
	int r = 0;

	boolean flag = false;
	int next;
	for(int i=1; i<=n; i++){
	    next = sc.nextInt();
	    if(flag){
		if(r-i+l != next){
		    System.out.println("0 0");
		    System.exit(0);
    		}
		if(r == i){
		    flag = false;
		}
	    }else{
		if(next != i){
		    if(r != 0){
			System.out.println("0 0");
			System.exit(0);
		    }
		    r = next;
		    l = i;
		    flag = true;
		}
	    }
	}
	System.out.println(l+" "+r);
    }

}