#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() using namespace std; int main(){ int n,x,y; cin>>n>>x>>y; if(y%x){ n=n-y/x; } else{ n=n-y/x-1; } if(n==0){ cout<<0; } else{ cout<<n; } return 0; }