#include <iostream>

#include <iostream>
using namespace std;
int main(){
int n,x,y;
cin >> n >> x >> y;
int eaten,ok;
eaten=y/x;
if (y%x!=0){
eaten+=1;
}
ok=n-eaten;
if(ok<0){
ok=0;
}
cout << ok;
return 0;
}