text: #include<iostream>
  using namespace std;
  
  int main(int argc, char* argv[])
  {
  
  	int n = 0;
  	int k = 0;
  	int m = 0;
  	int ans = 0;
  
  	cin >> k >> m >> n;
  
  	if (n <= k)
  	{
  		ans = 2 * m;
  	}
  	else if ((n * 2) % k == 0)
  	{
  		ans = m * ((n * 2) / k);
  	}
  	else
  	{
  		ans = m * (1 + ((n * 2) / k));
  	}
  
  	cout << ans;
  
  	return EXIT_SUCCESS;
  }