#include <stdio.h>

int main(){
	// 野菜の数・肉の数・比率・許容量
	int vegetables, meat, proportion, all;
	scanf("%d%d%d%d",&vegetables,&meat,&proportion,&all);
	if(vegetables + meat < all){
		printf("%d",meat / proportion);
	}else{
		printf("%d",all / (proportion + 1));
	}
}