#include<iostream>
#include<algorithm>
#include <vector>
using namespace std;
int main() {
	int A, B, C, D;
	cin >> A >> B >> C >> D;
	int X, Y;
	for (int i = 0; i < A; i++) {
		if (i * C > B) {
			break;
		}
		X = i + i * C;
		if (X > D) {
			break;
		}
		Y = i;
	}
	cout << Y << endl;
}