题解 | #KiKi和酸奶#

#include<iostream>
#include<cmath>

void calculate(const double& a, const double& b, const double& c)
{
	double surplus =a- std::ceil(c / b);  //std::ceil(double x)取大于等于该数的最小整数
	std::cout << static_cast<int> (surplus)<< std::endl; //强制类型转换符static_cast<type>(data)
}

int main(int argc, char* argv[])
{
	double n{}, h{}, m{};
	std::cin >> n >> h >> m;
	if (m <= n * h) {
		calculate(n, h, m);
	}
}