A603.苹果和虫子

#include<iostream>
using namespace std;
int main(){
    int n;
    int x;
    int 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;
}