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.*;

public class B {

	void run()throws IOException{
		BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(bf.readLine());
		int[] ar = new int[n+2];
		ar[0]=0;
		ar[n+1]=n+1;
		String[] s = bf.readLine().split("[ ]+");
		for(int i=1;i<=n;i++){
			ar[i]=Integer.parseInt(s[i-1]);
		}
		
		int st=0;
		int end=0;
		int chg=0;
		
		for(int i=1;i<ar.length;i++){
			if(Math.abs(ar[i]-ar[i-1])!=1){
				if(chg==0) st=i;
				if(chg==1) end=i-1;
				chg++;
			}
		}
		
		if(chg==2){
			System.out.println(st + " " + end);
		} else System.out.println("0 0");
	}
	
	public static void main(String[] args)throws IOException {
		new B().run();
	}
}