题解 100% AC

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