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.util.Arrays;
import java.util.Scanner;

/**
 *
 */
public class SolutionCF56B2 {
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        
        int[] inputs = new int[n];
        int[] base = new int[n];
        for (int i = 0; i < n; i++) {
            inputs[i] = base[i] = sc.nextInt();
        }
        Arrays.sort(base);
        int begin = 0;
        int end = base.length - 1;
        boolean firstFlag = true;
        while (begin <= end) {
            if (inputs[begin] != base[begin] && inputs[end] == base[end]) {
                end--;
            } else if (inputs[begin] == base[begin] && inputs[end] != base[end]) {
                begin++;
            } else if (inputs[begin] == base[begin] && inputs[end] == base[end]) {
                end--;
                begin++;
            } else {
                firstFlag = false;
                break;
            }
        }

        boolean flag = true;
        for (int i = begin; i < end; i++) {
            if (inputs[i] - inputs[i+1] != 1) {
                flag = false;
                break;
            }
        }
        if (firstFlag){
            System.out.println(0 + " " + 0);
        }else {
            if (flag) {
                System.out.println((begin + 1) + " " + (end + 1));
            } else {
                System.out.println(0 + " " + 0);
            }
        }
        
        
        
    }
    
    
}