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() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int num, cnt = 0, beg = -1, en = -1, c = 0;
  bool flag = false, enter = false;
  ;
  cin >> num;
  vector<int> vec(num + 1);
  vec[0] = 0;
  for (int i = 1; i <= (int)(num); i++) {
    cin >> vec[i];
    if (vec[i] != i && !flag) {
      flag = true;
      beg = i;
    }
  }
  for (int i = num; i >= 1; i--) {
    if (vec[i] != i) {
      en = i;
      break;
    }
  }
  if (beg == -1 && en == -1)
    cout << "0 0";
  else {
    for (int i = beg; i <= (beg + en) / 2; i++) swap(vec[i], vec[en - c++]);
    for (int i = 1; i <= (int)(num); i++) {
      if (vec[i] != i) {
        cout << "0 0";
        return 0;
      }
    }
    cout << beg << " " << en;
  }
  return 0;
}