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>
int main() {
  int n;
  std::cin >> n;
  std::vector<int> v(n + 1);
  for (int i = 1; i <= n; ++i) {
    std::cin >> v[i];
  }
  int left = 0;
  if (v[1] != 1) {
    left = 1;
  } else {
    for (int i = 2; i <= n; ++i) {
      if (v[i] != v[i - 1] + 1) {
        left = i;
        break;
      }
    }
  }
  if (left > 0) {
    int right = 0;
    if (v[n] != n) {
      right = n;
    } else {
      for (int i = n - 1; i > right; --i) {
        if (v[i] != v[i + 1] - 1) {
          right = i;
          break;
        }
      }
    }
    int i;
    for (i = left; i < right; ++i) {
      if (v[i] != v[i + 1] + 1) {
        break;
      }
    }
    if (i == right) {
      std::cout << left << " " << right << std::endl;
      return 0;
    }
  }
  std::cout << "0 0" << std::endl;
}