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;
import java.util.Arrays;

public class Main {
	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		
		int n = Integer.parseInt(r.readLine());
		String[] arr = r.readLine().split("[ ]+");
		int[] a = new int[n];
		int[] diff=  new int[n];
		
		for (int i = 0; i < a.length; i++) {
			a[i]= Integer.parseInt(arr[i]);
		}
		
		for (int i = 0; i < diff.length; i++) {
			diff[i] = a[i]-(i>0?a[i-1]:0);
		}
		boolean found = false;
		boolean cont = false;
		int start =0;
		int end = 0;
		for (int i = 0; i <= a.length; i++) {
			if(i<a.length && diff[i]<-1){
				System.out.println("0 0");
				System.exit(0);
				
			}
			if(i<a.length && diff[i]==-1){
				if(!found){
					found = true;
					cont = true;
					start = a[i-1];
				}else{
					if(!cont){
						System.out.println("0 0");
						System.exit(0);
					}
				}
			}else{
				if(cont){
					end = a[i-1];
					cont = false;
				}
			}
			
		}
		if(!found){
			System.out.println("0 0");
		}else{			
			System.out.println((end==0?1:end)+" "+start);
		}
		
	}
}