#include <iostream>
class Solution {
public:
static auto totalMoney(auto n) {
return (28 + n % 7) * (n / 7) + (n / 7) * (n / 7 - 1) / 2 * 7 + (1 + n % 7) * (n % 7) / 2;
}
};
int main() {
std::cout << Solution::totalMoney(20);
return 0;