# Enter your code here. Read input from STDIN. Print output to STDOUT
st = input()
n, d, m, s = map(int, st.split())
res = 0
while (s > 0):
	if (s < m or s < n):
		break
	if n > m:
		s-=n
		n -= d
	else:
		s-=m
	res += 1
print(res)