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 get(std::vector<int> &nums, int iter, int upd, int number) {
  while (iter >= 0 && iter < nums.size()) {
    if (nums[iter] == number) {
      iter += upd;
      number += upd;
    } else {
      return iter;
    }
  }
  return -1;
}
int main() {
  int n;
  std::cin >> n;
  std::vector<int> nums;
  for (int iter = 0; iter < n; ++iter) {
    int val;
    std::cin >> val;
    nums.push_back(val);
  }
  int id1 = get(nums, 0, 1, 1), id2 = get(nums, n - 1, -1, n);
  if (id1 == -1) {
    std::cout << "0 0";
    return 0;
  }
  int output = 1, number = id1 + 1;
  for (int iter = id2; iter >= id1; --iter, ++number) {
    if (nums[iter] != number) {
      output = 0;
    }
  }
  if (!output) {
    id1 = id2 = -1;
  }
  std::cout << id1 + 1 << " " << id2 + 1;
  return 0;
}