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 int n;
vector<long long int> v;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  long long int a[n];
  for (long long i = 0; i < n; i++) cin >> a[i];
  long long int flag = 0;
  long long int s = 0, e = 0, cnt = 0;
  if (n == 1)
    cout << "0 0";
  else {
    if (a[0] != 1)
      s = 0;
    else
      for (long long i = 1; i < n; i++) {
        if (a[i] - a[i - 1] != 1) {
          s = i;
          break;
        }
      }
    if (a[n - 1] != n)
      e = n - 1;
    else
      for (long long int i = n - 1; i > 0; i--) {
        if (a[i] - a[i - 1] != 1) {
          e = i - 1;
          break;
        }
      }
    if (s >= e) {
      cout << "0 0";
      return 0;
    } else
      for (long long i = s + 1; i < e + 1; i++) {
        if (a[i] - a[i - 1] != -1) {
          cout << "0 0";
          return 0;
        }
      }
    cout << s + 1 << " " << e + 1;
  }
  return 0;
}