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.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.StreamTokenizer;
import java.util.Arrays;
import java.util.Comparator;

public class Main {
    private static StreamTokenizer in;
    private static PrintWriter out;
    private static BufferedReader inB;
    
    private static int nextInt() throws Exception{
        in.nextToken();
        return (int)in.nval;
    }
    
    private static String nextString() throws Exception{
        in.nextToken();
        return in.sval;
    }
    
    static{
        inB = new BufferedReader(new InputStreamReader(System.in));
        in = new StreamTokenizer(inB);
        out = new PrintWriter(System.out);
    }
    
    private static void broke() {
        System.out.println("0 0");
        System.exit(0);
    }
    
    public static void main(String[] args)throws Exception{
        int n = nextInt();
        
        int[] mas = new int[n];
        boolean[] change = new boolean[n];
        
        for(int i = 0; i<n; i++) {
            mas[i] = nextInt();
            change[i] = mas[i] != (i+1);
        }
        
        int left = -1, right = -1;
        
        for(int i = 0; i<n; i++) {
            if(change[i]) {
                left = i;
                break;
            }
        }
        if(left == -1)broke();
        
        for(int i = n-1; i>=0; i--) {
            if(change[i]) {
                right = i;
                break;
            }
        }
        
        for(int i = left + 1; i<=right; i++) {
            if(mas[i] != mas[i-1] - 1)broke();
        }
        
        System.out.println((left+1) + " "+ (right + 1));
    }
}