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.*;
import java.io.*;

public class Main2 {
    public static void main(String[] args) throws Exception {
        solve();
        out.flush();
    }

    public static void solve() throws Exception {
        int n1 = ni();
        int[] l1 = nil(n1);
        if (n1 == 1){
            pn("0 0");
        }
        else {
            int head = 0;
            for (int i =0; i < n1; i++){
                if (l1[i]!=i+1)break;
                head= i + 1;
            }
            int tail = n1 - 1;
            for (int i =0; i < n1; i++){
                if (l1[n1 - 1 - i]!= n1 - i) break;
                tail--;
            }
//          px(head, tail);
            if (tail <= head){
                pn("0 0");
                return;
            }
            for (int i = head; i <= tail;i++){
//              px(l1[i]+i );
                if (l1[i] + i + 1 != head + tail + 2){
                    pn("0 0");
                    return;
                }
            }
            pn(head+1+ " " + (tail + 1));
        }
    }

    public static BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    public static StringTokenizer st = null;

    public static String nx() throws Exception {
        for (; st == null || !st.hasMoreTokens();) {
            String k1 = in.readLine();
            if (k1 == null) return null;
            st = new StringTokenizer(k1);
        }
        return st.nextToken();
    }

    public static int ni() throws Exception {
        return Integer.parseInt(nx());
    }

    public static long nl() throws Exception {
        return Long.parseLong(nx());
    }

    public static double nd() throws Exception {
        return Double.parseDouble(nx());
    }

    private static int[] nil(int n1) throws Exception {
        int[] l1 = new int[n1];
        for (int i = 0; i < n1; i++) {
            l1[i] = ni();
        }
        return l1;
    }

    public static void px(Object... l1) {
        System.out.println(Arrays.deepToString(l1));
    }

    public static boolean FLUSH = false;
    public static PrintWriter out = new PrintWriter(System.out, FLUSH);

    public static void p(Object... l1) {
        for (int i = 0; i < l1.length; i++) {
            if (i != 0) out.print(' ');
            out.print(l1[i].toString());
        }
    }

    public static void pn(Object... l1) {
        for (int i = 0; i < l1.length; i++) {
            if (i != 0) out.print(' ');
            out.print(l1[i].toString());
        }
        out.println();
    }

}