#include <iostream>
using namespace std;
int main(){
	int A,B,C,D,sum=0;
	cin>>A>>B>>C>>D;
	while((A>=0)&&(B>=0)&&(D>=0)){
		A--;
		B-=C;
		D-=(C+1);
		sum++;
	}
	sum--;
	cout<<sum<<endl;
	return 0;
}