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>
void __check(const char* expr, const char* file, unsigned int line) {
  printf("%s:%u: failed check `%s'\n", file, line, expr);
  abort();
}
using namespace std;
template <typename T>
bool uin(T& a, T b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
bool uax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
int sz(const T& t) {
  return static_cast<int>(t.size());
}
template <typename T>
void shrink(std::vector<T>& v) {
  std::vector<T>(v).swap(v);
}
const bool DBG = false;
long long get_pow(long long n, int p) {
  long long res = 1;
  for (int i = 0; i < (int)(p); ++i) {
    res *= n;
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(false);
  int n;
  cin >> n;
  cout << (n % 2 == 0 ? get_pow(2, n / 2) : 0) << endl;
  return 0;
}
