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 INF = 1e9 + 1000;
const long long INF64 = 1e18 + 1000;
const int N = 6 * 100 * 1000 + 100;
const int MOD = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  if (n % 2) {
    cout << 0;
    return 0;
  }
  vector<int> dp(n + 1);
  dp[2] = 2;
  for (int i = 4; i <= n; i += 2) {
    dp[i] = dp[i - 2] * 2;
  }
  cout << dp[n];
}
