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 CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int main() {
  int all;
  cin >> all;
  vector<int> a;
  for (int i = 0; i < all; i++) {
    int tmp;
    cin >> tmp;
    a.push_back(tmp);
  }
  int answer[2] = {};
  int up = 0;
  int bot = 0;
  bool flag = true;
  for (int i = 0; i < a.size(); i++) {
    if (i + 1 != a[i]) {
      if (up == 0) {
        up = a[i];
        bot = i + 1;
      } else if (up < i + 1 || bot > i + 1) {
        flag = false;
      }
    }
  }
  if (flag == true) {
    answer[0] = bot;
    answer[1] = up;
  }
  for (int i = 0; i < up - bot; i++) {
    if (a[bot + i - 1] != up - i) {
      answer[0] = 0;
      answer[1] = 0;
    }
  }
  cout << answer[0] << " " << answer[1] << endl;
  return 0;
}