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<int> vec(n + 1);
  vector<int> vec1(n + 1);
  vec[n] = 1000000;
  for (int i = 0; i <= n; i++) {
    cin >> vec[i];
    vec1[i] = vec[i];
  }
  int re = 0;
  int l = 0;
  int r = 0;
  for (int i = 0; i < n; i++) {
    if (re == 0) {
      if (vec[i] > vec[i + 1]) {
        re = 1;
        l = i;
      }
    }
    if (re == 1) {
      if (vec[i] < vec[i + 1]) {
        re = 2;
        r = i;
      }
    }
    if (re == 2) {
      if (vec[i] > vec[i + 1]) {
        cout << 0 << " " << 0;
        return 0;
      }
    }
  }
  int y = l;
  int h = r;
  for (int j = l; h >= l; j++) {
    vec1[y] = vec[h];
    h -= 1;
    y++;
  }
  for (int m = 0; m < n; m++) {
    if (vec1[m] > vec1[m + 1]) {
      cout << 0 << " " << 0;
      return 0;
    }
  }
  if (l == 0 && r == 0) {
    cout << l << " " << r;
    return 0;
  }
  cout << l + 1 << " " << r + 1;
}