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.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class problem56B {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n+1];
		for(int i=1;i<=n;i++) arr[i] = sc.nextInt();
		int start = -1;
		for(int i=1;i<=n;i++){
			if(i!=arr[i]){
				start = i;
				break;
			}
		}
		int end = -1;
		for(int i=1;i<=n;i++){
			if(i!=arr[i]){
				end = i;
			}
		}
		if(start!=-1){
			ArrayList<Integer> list = new ArrayList<>();
			for(int i=1;i<start;i++){
				list.add(arr[i]);
			}
			for(int i=end;i>=start;i--){
				list.add(arr[i]);
			}
			for(int i=end+1;i<=n;i++){
				list.add(arr[i]);
			}
			ArrayList<Integer> tmp = (ArrayList<Integer>) list.clone();
			Collections.sort(tmp);
			if(tmp.equals(list)){
				System.out.println(start+" "+end);
			}
			else{
				System.out.println(0+" "+0);
			}
		}
		else{
			System.out.println(0+" "+0);
		}
	}

}