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(void) {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  vector<int> A(n);
  for (long long int i = 0; i < n; i++) {
    cin >> A[i];
  }
  bool is = false;
  int start;
  for (int i = 0; i < n; i++) {
    if (A[i] != i + 1) {
      start = i;
      is = true;
      break;
    }
  }
  if (!is) {
    cout << "0 0\n";
  } else {
    int where = -1;
    for (int i = start + 1; i < n; i++) {
      if (A[i] == start + 1) {
        where = i;
        break;
      }
    }
    is = true;
    reverse(A.begin() + start, A.begin() + where + 1);
    for (int i = start; i < where; i++) {
      if (A[i] != i + 1) {
        is = false;
        break;
      }
    }
    if (!is) {
      cout << "0 0\n";
    } else {
      is = true;
      for (int i = where + 1; i < n; i++) {
        if (A[i] != i + 1) {
          is = false;
          break;
        }
      }
      if (is) {
        cout << start + 1 << " " << where + 1 << endl;
      } else {
        cout << "0 0\n";
      }
    }
  }
  return (0);
}