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:
//package round52;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class B {

	static BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
	static StringTokenizer st;
	static PrintWriter out = new PrintWriter(System.out);
	
	static String nextToken() throws IOException{
		while (st==null || !st.hasMoreTokens()){
			String s = bf.readLine();
			if (s == null)
				return null;
			st = new StringTokenizer(s);
		}
		
		return st.nextToken();
	}
	
	static int nextInt() throws IOException{
		return Integer.parseInt(nextToken());
	}
	
	static String nextStr() throws IOException{
		return nextToken();
	}
	
	static double nextDouble() throws IOException{
		return Double.parseDouble(nextToken());
	}
	
	public static void main(String[] args) throws IOException{
		int n = nextInt(),
			a[] = new int[n];
		
		int l = -1, r = -1;
		
		for (int i=0; i<n; i++)
			a[i] = nextInt();
		
		if (a[0] != 1)
			l = 0;
		if (a[n-1] != n)
			r = n;
		
		for (int i=1; i<n; i++)
			if (Math.abs(a[i]-a[i-1]) != 1){
				if (l == -1)
					l = i;
				else if (r == -1)
					r = i;
				else{
					out.println("0 0");
					out.flush();
					return;
				}
			}
		
		if (l==-1 || r==-1){
			out.println("0 0");
			out.flush();
			return;
		}
		
		for (int i=l+1; i<r; i++)
			if (a[i] != a[i-1]-1){
				out.println("0 0");
				out.flush();
				return;
			}
		
		l++;
		out.println(l+" "+r);
		out.flush();
	}

}