#include<iostream>
using namespace std;
int main()
{
	int m,t,s;
	cin >> m >> t >> s;
	if (t == 0)
	{
		cout << "0";
	}
	else
	{
		int a = m - ceil(s * 1.0 / t);
		if (a > 0)
		{
			cout << a;
		}
		else
		{
			cout << "0";
		}
	}

}

}