#include using namespace std; int main() { long long a; long long b; long long c; long long d; long long mid=1; long long ans=0; cin >> a; b = a / 2; c = a / 2; d = a / 2; if (a % 2 == 0) { for (int i = 0; i <= c; i++) { if (d - b > b) { for (int j = 0; j < b; j++) { mid = mid * (d - j); } for (int k = 0; k < b; k++) { mid = mid / (b - k); } } else { for (int j = 0; j < d-b; j++) { mid = mid * (d - j); } for (int l = 0; l < (d - b); l++) { mid = mid / (d - b - l); } } cout << mid< b) { for (int j = 0; j < b; j++) { mid = mid * (d - j); } for (int k = 0; k < b; k++) { mid = mid / (b - k); } } else { for (int j = 0; j < d - b; j++) { mid = mid * (d - j); } for (int l = 0; l < (d - b); l++) { mid = mid / (d - b - l); } } cout << mid << endl; ans = ans + mid; mid = 1; d++; b--; } } cout << ans; return 0; }