#include<stdio.h>
int main()
{
	int a, b, c, d;
	scanf("%d %d %d %d", &a, &b, &c, &d);
	int ans;
	for (ans = 0; ans <= a; ans++)
	{
		if (b < ans * c)
			break;
		if (ans * (c + 1) > d)
			break;
	}
	ans--;
	printf("%d\n", ans);
	return 0;
}