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;

/**
 *
 * @author jimmy
 */
public class Problem56B {

    public static void main(String args[]) {
        Scanner s = new Scanner(System.in);

        int n = s.nextInt();
        int mas[] = new int[n];

        for(int i = 0; i < n; i++) {
            mas[i] = s.nextInt();
        }

        int counter = 0;
        int a = 1, b = n;
        boolean isChanged = false;


        for(int i = 1; i < n; i++) {
            if(Math.abs(mas[i] - mas[i - 1]) != 1) {
                counter++;
                if(counter == 1)
                    a = i + 1;
                else b = i;
            }
            if(mas[i] - mas[i - 1] < 0) isChanged = true;
        }
        //System.out.println(counter + " " + isChanged + "a = " + a + " b = " + b);
        if((counter == 2 || counter == 0) && isChanged) {
            System.out.println(a + " " + b);
            return;
        } else if(counter == 1) {
            if((a == n - 1 && b == n) || (a == 2 && b == n)) {
                System.out.println(a + " " + b);
                return;
            }
        } 

        System.out.println("0 0");
    }

}