#define _USE_MATH_DEFINES #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define rep(i, N) for (int i = 0; i < N; i++) #define pb push_back typedef long long ll; typedef unsigned long long ull; typedef pair i_i; typedef pair ll_i; typedef pair i_ll; typedef pair d_i; typedef pair ll_ll; typedef pair d_d; struct edge { int v; ll w; }; const int MOD = 1000000007; ll _MOD = 1000000009; double EPS = 1e-10; int INF = INT_MAX / 2; int a[] = {0, 2, 4, 9, 18, 37, 75, 150, 300, 600, 1200}; int main() { int N; cin >> N; cout << a[N] << endl; }