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 gcd(int a, int b) {
  if (b > a) return gcd(b, a);
  return b == 0 ? a : gcd(b, a % b);
}
void swap(int *m, int *n) {
  int temp = *n;
  *n = *m;
  *m = temp;
}
struct sort_pred {
  bool operator()(const std::pair<int, int> &left,
                  const std::pair<int, int> &right) {
    return left.first < right.first;
  }
};
int compare(const void *a, const void *b) {
  const int *ia = (const int *)a;
  const int *ib = (const int *)b;
  return *ia - *ib;
}
int a[1000];
int b[1000];
int main() {
  int n;
  scanf("%d", &n);
  int i, j;
  int k = 0;
  int prev = -1;
  int uniflag = 0;
  int begin = -1, end = -1, flag = 0, flag1 = 0;
  for (i = 0; i < n; i++) {
    scanf("%d", &a[i]);
    if (a[i] != i + 1 && flag == 0) {
      begin = i + 1;
      flag = 1;
      b[k++] = a[i];
      prev = a[i];
    } else if (a[i] == prev - 1) {
      end = i + 1;
      b[k++] = a[i];
      prev = a[i];
    } else if (prev != -1 && a[i] != i + 1) {
      uniflag = 1;
    }
  }
  int len = end - begin + 1;
  sort(b, b + len);
  int count1 = 0;
  for (i = 0; i < len; i++) {
    if (b[i] == begin + i) count1++;
  }
  if (uniflag == 1)
    cout << "0 0" << endl;
  else if (count1 == len)
    cout << begin << " " << end << endl;
  else
    cout << "0 0" << endl;
  return 0;
}