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.awt.Point;
import java.io.*;
import java.math.BigInteger;
import java.util.*;

import static java.lang.Math.*;

public class Testt {

    final boolean ONLINE_JUDGE = System.getProperty("ONLINE_JUDGE") != null;
    BufferedReader in;
    PrintWriter out;
    StringTokenizer tok = new StringTokenizer("");

    void init() throws FileNotFoundException {
        if (ONLINE_JUDGE) {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
        } else {
            in = new BufferedReader(new FileReader("input.txt"));
            out = new PrintWriter("output.txt");
        }
    }

    String readString() throws IOException {
        while (!tok.hasMoreTokens()) {
            tok = new StringTokenizer(in.readLine());
        }
        return tok.nextToken();
    }

    int readInt() throws IOException {
        return Integer.parseInt(readString());
    }

    long readLong() throws IOException {
        return Long.parseLong(readString());
    }

    double readDouble() throws IOException {
        return Double.parseDouble(readString());
    }

    public static void main(String[] args) {
        new Testt().run();
    }

    public void run() {
        try {
            long t1 = System.currentTimeMillis();
            init();
            solve();
            out.close();
            long t2 = System.currentTimeMillis();
            System.err.println("Time = " + (t2 - t1));
        } catch (Exception e) {
            e.printStackTrace(System.err);
            System.exit(-1);
        }
    }
    
    
    void solve() throws IOException {
        int n = readInt();
        int [] a = new int [n];
        int x=0;
        int y = 0;
        for (int i = 0; i<n; i++){
                a[i] = readInt();
                if (a[i]-1==x){x=a[i]; y++;}
        }
        if (y==n) { out.print(0 + " " + 0); return;}
        int m=1;
        for (int i =0; i<n-1;i++){
                if (a[i]-1 ==a[i+1]) m++;
                else break;
        }
        if (n==m) { out.print(1 + " " + n); return;}
        for (int i = 0; i<n-1; i++)
                if (a[i] !=a[i+1]-1){x=i+1; break;}
        for (int i=n-1; i>0;i--){
                if (a[i]-1 !=a[i-1]){if (a[n-1]!=n)y=i+1;
                                    else y=i;  break;}
        }
        int j=0;
        int l;
        if (n%2==1) l=0;
        else l=1;
        for (int i =1; i <= (y-x)/2;i++){
                int k = a[x+j];
                a[x+j]=a[y-j-1];
                a[y-j-1]=k;
                j++;
        }
        x++;
        for (int i = 0; i <n-1; i++)
                if (a[i]+1!=a[i+1]){ out.print(0 + " " + 0); return;}
        out.print(x + " " + y);
}
}