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;
  cin >> n;
  vector<pair<int, int>> arr;
  vector<int> t;
  for (int i = 0; i < n; i++) {
    int a;
    cin >> a;
    t.push_back(a);
    arr.push_back({a, i});
  }
  sort(arr.begin(), arr.end());
  int i, j;
  for (i = 0; i < arr.size(); i++) {
    if (arr[i].second != i) break;
  }
  for (j = arr.size() - 1; j >= 0; j--) {
    if (arr[j].second != j) break;
  }
  if (i == arr.size() || j < 0)
    cout << 0 << " " << 0 << endl;
  else {
    vector<int> res;
    for (int k = 0; k < i; k++) res.push_back(t[k]);
    for (int k = j; k >= i; k--) res.push_back(t[k]);
    for (int k = j + 1; k < n; k++) res.push_back(t[k]);
    bool flag = false;
    for (int k = 0; k < n - 1; k++) {
      if (res[k] >= res[k + 1]) {
        flag = true;
        break;
      }
    }
    if (!flag)
      cout << arr[j].second + 1 << " " << arr[i].second + 1 << endl;
    else
      cout << 0 << " " << 0 << endl;
  }
  return 0;
}