#include<stdio.h>

int main()
{
	int vegetables, meat, multiple, full;
	scanf("%d %d %d %d",&vegetables,&meat,&multiple,&full);
	int ans = 0;
	for (ans = 0; ans <= vegetables; ans++)
	{
		if (meat < ans * multiple){
			break;
		}
		if (ans * (multiple + 1) > full){
			break;
		}
	}
	ans--;
	printf("%d\n", ans);
}