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.HashSet;


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