#include <bits/stdc++.h>
using namespace std;
int main()
{
 int m,x,y;
 double t,s;
 cin>>m>>t>>s;
 if(!s) return 0;
 x=ceil(s/t);
 y=m-x;
 if(m<0)
  return 0;
 else
  cout<<y;
 return 0;
}