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.InputStreamReader;
import java.util.StringTokenizer;

public class SpoiltPermutation {

    void run() {
        try {
            BufferedReader bfd = new BufferedReader(new InputStreamReader(
                    System.in));
            int n = Integer.parseInt(bfd.readLine()), i, arr[] = new int[n];
            StringTokenizer tok = new StringTokenizer(bfd.readLine());
            for(i=0; i<n; ++i)
                arr[i] = Integer.parseInt(tok.nextToken());
            int stInd = -1, endInd = -1;
            for(i=0; i<n; ++i)
                if(arr[i]!=i+1) {
                    stInd = i;
                    break;
                }
            for(i=n-1; i>=0; --i)
                if(arr[i]!=i+1) {
                    endInd = i;
                    break;
                }
            boolean res = true;
            i = endInd;
            while(i>stInd && res) {
                if(arr[i]>arr[i-1])
                    res = false;
                --i;
            }
            if(res) System.out.println(stInd+1+" " + (endInd+1));
            else System.out.println("0 0");
        } catch (Exception e) {

        }
    }
    public static void main(String[] args) {
        new SpoiltPermutation().run();
    }

}