#include <bits/stdc++.h>
using namespace std;
int main()
{
	int m,t,s,d,sum;
	cin>>m>>t>>s;
	if(s==0)
	{
		cout<<0;
	}
	if(s%t>=1)
	{
		d=s/t+1;
		sum=m-d;
	}
	else
	{
		d=s/t;
		sum=m-d;
	}
	cout<<sum;
}