#include<iostream>
using namespace std;
int main()

{
	double m,t,s;
	cin >> m >> t >> s;
	if (t = 0) {
		cout << "0";
	}
	else {
		cout << m - ceil(s/t);

	}
		
		
		
	
		
		
		
		
		
	return 0;
}