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 Main {

	/**
	 * @param args
	 * @throws IOException 
	 * @throws NumberFormatException 
	 */
	public static void main(String[] args) throws NumberFormatException, IOException {
		// TODO Auto-generated method stub
		BufferedReader r=new BufferedReader(new InputStreamReader(System.in));
		int n=Integer.parseInt(r.readLine());
		int[] nums=new int[n];
		String l=r.readLine();
		String[] sp=l.split(" ");
		for (int i = 0; i < sp.length; i++) {
			nums[i]=Integer.parseInt(sp[i]);
		}
		int firstI = 0;
		int lastI = 0;
		boolean first=true;
		for(int i=0;i<nums.length;i++){
			if(nums[i]!=i+1){
				if(first){
					first=false;
					firstI=i;
					
				}
				else{
					lastI=i;
				}
			}
		}
		if(first){
			System.out.println("0 0");
		}
		else{
		int c=0;
		boolean f=true;
		for(int i=firstI;i<=lastI;i++){
			if(nums[i]!=lastI+1-c++)
				f=false;
		}
		if(f){
			System.out.println(firstI+1+" "+(lastI+1));
		}
		else
			System.out.println("0 0");
	}
	}

}