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;
long long labs(long long a) { return a < 0 ? (-a) : a; }
long long max(long long a, long long b) { return a > b ? a : b; }
long long min(long long a, long long b) { return a < b ? a : b; }
template <typename T>
struct Point {
  bool first;
  T x, y;
  Point() {}
  Point(T xx, T yy) : x(xx), y(yy) {}
};
template <typename T>
bool operator<(const Point<T> &p1, const Point<T> &p2) {
  return p1.x < p2.x || p1.x == p2.x && p1.y < p2.y;
}
vector<int> v;
int main() {
  int n;
  cin >> n;
  v.resize(n);
  for (int(i) = 0; (i) < (n); (i)++) {
    cin >> v[i];
  }
  bool b = 0;
  int l = 0, r = 0;
  for (int(i) = 0; (i) < (n); (i)++) {
    if (v[i] != i + 1) {
      if (b) {
        cout << "0 0";
        return 0;
      }
      b = 1;
      int a = v[i];
      int from = i;
      l = from + 1;
      r = a;
      for (int j = a - 1; j >= from; j--, i++) {
        if (v[j] != i + 1) {
          cout << "0 0";
          return 0;
        }
      }
    }
  }
  cout << l << " " << r;
  return 0;
}