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 n = 0, temp = 0;
  int flag = 0, index1 = 0, index2 = 0;
  std::vector<int> v, v1;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> temp;
    v.push_back(temp);
    v1.push_back(i + 1);
  }
  for (int i = 0; i < n - 1; i++) {
    if (v[i] - v[i + 1] != 1 && v[i] > v[i + 1]) {
      cout << 0 << "	" << 0 << "	" << endl;
      return 0;
    }
    if (v[i] - v[i + 1] == 1 && flag == 0) {
      index1 = i + 1;
      while (v[i] - v[i + 1] == 1 && i < n - 1) {
        i++;
      }
      flag = 1;
      index2 = i + 1;
    } else if (flag == 1 && v[i] > v[i + 1]) {
      cout << 0 << "	" << 0 << "	" << endl;
      return 0;
    }
  }
  if (flag == 1)
    cout << index1 << "	" << index2 << "	" << endl;
  else
    cout << 0 << "	" << 0 << "	" << endl;
  return 0;
}