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 com.sun.jdi.ArrayReference;
import jdk.swing.interop.SwingInterOpUtils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.Array;
import java.math.BigInteger;
import java.text.DecimalFormat;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        FastScanner fs = new FastScanner();
        //finne left og right av første snudde array
        int n = fs.nextInt();
        int[] a = fs.readArray(n);
        int l = -1;
        int r = -1;
        boolean found = false;
        for (int i = 0; i<n; i++) {
            if (found) break;

            if (a[i] != i+1) {
                int j = i;
                l = i;
                int shouldBe = i+1;
                while (true) {
                    if (j==n) {
                        r = j-1;
                        found = true;
                        break;
                    }
                    if (a[j] == shouldBe) {
                        r = j;
                        found = true;
                        break;
                    } else {
                        j++;
                    }
                }
            }
        }
        int[] ans = new int[n];
        int current = 0;
        if (l == -1 || r == -1) {
            System.out.println(0 + " " + 0);
        } else {
            for (int i = 0; i<l; i++) {
                ans[current] = a[i];
                current++;
            }
            for (int i = r; i>=l; i--) {
                ans[current] = a[i];
                current++;
            }
            for (int i = r+1; i<n; i++) {
                ans[current] = a[i];
                current++;
            }
            Arrays.sort(a);
            boolean hasAns = true;
            for (int i = 0; i<n; i++) {
                if (ans[i] != a[i]) {
                    hasAns = false;
                    break;
                }
            }
            if (hasAns) {
                System.out.println((l+1) + " " + (r+1));
            } else {
                System.out.println(0 + " " + 0);
            }
        }


    }
    public static void arrayPrinter(int[] a) {
        for (int i = 0; i<a.length; i++) {
            System.out.print(a[i] + " ");
        }
        System.out.println();
    }


    static class FastScanner {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st=new StringTokenizer("");
        String next() {
            while (!st.hasMoreTokens())
                try {
                    st=new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
        int[] readArray(int n) {
            int[] a=new int[n];
            for (int i=0; i<n; i++) a[i]=nextInt();
            return a;
        }
        long nextLong() {
            return Long.parseLong(next());
        }
    }

}