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 Contest52_2 {
    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(in.readLine());
        String []s = in.readLine().split(" ");
        int [] inp = new int [n];
        for (int i = 0; i < inp.length; i++) {
            inp[i] = Integer.parseInt(s[i]);
        }
        int [] r = new int [n];
        for (int i = 0; i < r.length; i++) {
            r[i] = i+1;
        }
        boolean flag1 = false;
        int a = 0;
        int b = 0;
        for (int i = 0; i < inp.length; i++) {
            if(inp[i]!=r[i] && !flag1){
                flag1 = true;
                int curr = inp[i]-1;
                a = i+1;
                int j = i+1;
                //System.out.println(j);
                for (j = i+1; j < inp.length; j++) {
                    if(inp[j]!=curr){
                        break;
                    }else
                        curr--;
                //  System.out.println(curr);
                }
                b = j;
                i = j-1;
            }else if(inp[i]!=r[i] && flag1){
                a = 0; b = 0;
                break;
            }
        }
        System.out.println(a+" "+b);
    }
}