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;
const int N = 1e5 + 5;
const int inf = 1e9 + 1;
const int prime_100000000 = 5761460;
const double eps = 1e-15;
const double EPS = 1e-9;
const double PI = acos(-1.0);
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long lcm(long long a, long long b) { return a * b / gcd(a, b); }
int main() {
  ios_base ::sync_with_stdio(false);
  cin.tie(NULL);
  long long n;
  cin >> n;
  (n & 1) ? cout << 0 << endl
          : cout << fixed << setprecision(0) << (pow(2, n / 2)) << endl;
}
