You have a given integer n. Find the number of ways to fill all 3 × n tiles with the shape described in the picture below. Upon filling, no empty spaces are allowed. Shapes cannot overlap.

<image> This picture describes when n = 4. The left one is the shape and the right one is 3 × n tiles. 

Input

The only line contains one integer n (1 ≤ n ≤ 60) — the length.

Output

Print the number of ways to fill.

Examples

Input


4


Output


4

Input


1


Output


0

Note

In the first example, there are 4 possible cases of filling.

In the second example, you cannot fill the shapes in 3 × 1 tiles.
#include <bits/stdc++.h>
using namespace std;
void swwap(int *a, int *b) {
  int temp = *a;
  *a = *b;
  *b = temp;
}
int bbinary_search(int val, int low, int high, vector<pair<int, int> > vec) {
  int mid = (low + high) / 2;
  while (low < high) {
    if (vec[mid].first == val)
      return mid;
    else if (vec[mid].first > val)
      high = mid - 1;
    else
      low = mid + 1;
  }
  return low;
}
void print_arr(int arr[], int n) {
  for (int i = 0; i < n; i++) {
    cout << arr[i] << " ";
  }
  cout << endl;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  if (n % 2 == 0) {
    int k = n / 2;
    long long int ans = 1;
    for (int i = 0; i < k; i++) {
      ans = ans << 1;
    }
    cout << ans << endl;
  } else
    cout << "0" << endl;
  return 0;
}
