#include <iostream>
using namespace std;

int main(){
    int A,B,C,D;
    int veg=-1,i,j;
    int total=0;

    cin>>A>>B>>C>>D;
    
    do{
        veg++;
        total=veg+veg*C;
    }while(total<=D && veg<=A && veg*C<D);

    cout<<veg-1<<endl;
    return 0;
}