#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<map>
#define all(x) x.begin(),x.end()
#define pb push_back
#define ll long long 
#define P pair<int,int>
#define LP pair<ll,ll>
using namespace std;
int main() {
	int a, b, c,d;
	cin >> a>>b>>c>>d;
	if (a > b/c) cout << d / (c + 1) << endl;
	else cout <<min( a, d/(c+1)) << endl;
	return 0;
}