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() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  int arr[n + 1];
  for (int i = 1; i <= n; i++) cin >> arr[i];
  if (n == 1)
    cout << "0 0";
  else if (n == 2) {
    if (arr[1] < arr[2])
      cout << "0 0";
    else
      cout << "1 2";
  } else {
    int a = -1, b = -1, cnt1 = 0, cnt2 = 0;
    for (int i = 2; i <= n - 1; i++) {
      if (arr[i] > arr[i - 1] && arr[i] > arr[i + 1]) {
        a = i;
        cnt1++;
      }
      if (arr[i] < arr[i - 1] && arr[i] < arr[i + 1]) {
        b = i;
        cnt2++;
      }
    }
    if (cnt1 > 1 || cnt2 > 1)
      cout << "0 0";
    else {
      if (a > 0 && b == -1 && arr[n] == arr[a - 1] + 1)
        cout << a << " " << n;
      else if (b > 0 && a == -1 && arr[b + 1] == arr[1] + 1)
        cout << 1 << " " << b;
      else if (arr[a] + 1 == arr[b + 1] && arr[b] == arr[a - 1] + 1)
        cout << a << " " << b;
      else
        cout << "0 0";
    }
  }
  return 0;
}