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.IOException;
import java.io.InputStreamReader;


public class SpoiltPermutation {

	/**
	 * @param args
	 * @throws IOException 
	 * @throws NumberFormatException 
	 */
	public static void main(String[] args) throws NumberFormatException, IOException 
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		
		String array [] = br.readLine().split(" ");
		
		int l = 1, r = 0, j;
		boolean flag = true;
		for(int i = 0; i < n && flag; i++)
		{
			int temp = Integer.parseInt(array[i]);
			
			if(temp != i + 1)
			{
				l = i + 1;
				r = temp;
				j = r - 1;
				i++;
				for(; i < n && flag; i++)
				{
					temp = Integer.parseInt(array[i]);
					if(temp != j)
						flag = false;
					else if (i + 1 == r)
					{
						i++;
						for(; i < n && flag; i++)
						{
							temp = Integer.parseInt(array[i]);
							if(i + 1 != temp)
								flag = false;
						}
					}
					j--;
				}
			}
		}
		if(flag && r > l)
			System.out.println(l + " " + r);
		else
			System.out.println("0 0");
	}

}