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.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Scanner;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author pttrung
 */
public class B {

    public static void main(String[] args) {
        Scanner in = new Scanner(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(System.out);
        int n = in.nextInt();
        int[] data = new int[n];
        for (int i = 0; i < n; i++) {
            data[i] = in.nextInt();
        }
        // boolean []decrease = new boolean[n];        
        int start = -1;
        int end = -1;
        int pre = -1;
        boolean found = true;
        boolean cons = false;
        for (int i = 0; i < n; i++) {
            if (data[i] != i + 1) {
                if (start == -1) {
                    start = i;
                    pre = data[i];
                    cons = true;
                } else if(end != -1){
                    found = false;
                    break;
                }
                
            }
            if(cons){
                if(data[i] == pre){
                    pre--;
                }else{
                    end = i - 1;
                    cons = false;
                }
            }
        }
   //     System.out.println(start + " " + end);
        if (!found || start == -1) {
            out.println(0 + " " + 0);
        } else {
            if (end == -1) {
                end = n - 1;
            }
          //  System.out.println(start + " " + end);
//            int val = data[start];
//
//            for (int i = start; i <= end; i++) {
//                if (data[i] != val) {
//                    found = false;
//                    break;
//                }
//                val--;
//            }
            if (!found) {
                out.println(0 + " " + 0);
            } else {
                out.println((data[end]) + " " + (data[start]));
            }
        }


        out.close();
    }

    public double pow(double a, int b) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        double val = pow(a, b / 2);
        if (b % 2 == 0) {
            return val * val;
        } else {
            return val * val * a;
        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long lcm(long a, long b) {
        return a * b / gcd(a, b);
    }
}