#include<iostream> 
#include<cstring>
#include<cmath>
//#include<algorithm>
//#include<iomanip>  cout<<fixed<<setprecision()
using namespace std;

int main(){
	int	 m,t,s;
	cin>>m>>t>>s;
	m=abs(int(m));
	t=abs(int(t));
	s=abs(int(s));	
	if(t==0){
		cout<<0;
		return 0;
	}
	if(s%t!=0){
		cout<<m-s/t-1;
	}else{
		cout<<m-s/t;
	}
	
	return 0;
}