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.*;
import java.util.*;
public class Main {
    public static void main(String[] args) throws Exception {      
        Reader.init(System.in);                
        int n = Reader.nextInt() ; 
        int [] a = new int [n] ;
        boolean is = false ; 
        int x = -1 , y = -1 ; 
        for (int i=0 ; i<n ; i++) {
            a[i]=Reader.nextInt() ; 
        }
        for (int i=0 ; i<n-1 ; i++) {
            if (a[i]>a[i+1]) {
                is = true ;
                if (x>-1)
                    y=i+1;
                else {
                    x=i; 
                    y=i+1 ;
                }
            } else if (is) 
                break ; 
        }
        for (int i=x , j=y ; i<j ; i++ , j--) {
            int temp = a[i] ; 
            a[i] = a[j] ; 
            a[j] = temp ; 
        }
        System.out.println((isSorted(a))?(x+1)+" "+(y+1):0+" "+0);       
    }     
    public static int BS(int[] a, int key) {
        int low = 0;
        int high = a.length - 1;
        while (low <= high) {
            int mid = low + (high - low) / 2;
            if (mid == key ) {
                return a[mid];
            } else if (mid < key) {
                low = mid + 1;
            } else {
                high = mid - 1;
            }
        }
        return -1;
    }

    public static boolean isSorted(int[] a) {

        int i;
        for (i = 0; i < a.length - 1; i++) {
            if (a[i] < a[i + 1]) {
                continue;
            } else {
                return false;
            }
        }
        return true;
    }

    public static void fill(int[] a) throws Exception {
        for (int i = 0; i < a.length; i++) {
            a[i] = Reader.nextInt();
        }
    }

    static void s(int[] cc) {
        for (int e = 0; e < cc.length; e++) {
            for (int q = e + 1; q < cc.length; q++) {
                if (cc[e] < cc[q]) {
                    int g = cc[e];
                    cc[e] = cc[q];
                    cc[q] = g;
                }
            }
        }

    }

    static boolean isPalindrome(String s) {
        int n = s.length();
        for (int i = 0; i < (n / 2) + 1; ++i) {
            if (s.charAt(i) != s.charAt(n - i - 1)) {
                return false;
            }
        }

        return true;
    }
}
class MyPair
{
     String s ;
     int x;
     int y;

    public MyPair(String s,int x, int y)
    {
        this.s = s;
        this.x = x;
        this.y = y;
    }

}
class Reader {

    static BufferedReader reader;
    static StringTokenizer tokenizer;

    /**
     * call this method to initialize reader for InputStream
     */
    static void init(InputStream input) {
        reader = new BufferedReader(
                new InputStreamReader(input));
        tokenizer = new StringTokenizer("");
    }

    /**
     * get next word
     */
    static String next() throws IOException {
        while (!tokenizer.hasMoreTokens()) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                    reader.readLine());
        }
        return tokenizer.nextToken();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

    static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static long nextLong() throws IOException {
        return Long.parseLong(next());
    }
}