# 백준 23351 - 물 주기
# 분류 : 우선순위 큐
from queue import PriorityQueue
N, K, A, B = map(int, input().split())
N //= A
pq = PriorityQueue()
for _ in range(N) :
pq.put(K)
count = 0
zero = 0
while True :
x = pq.get()
if x == zero :
break
x += B
zero += 1
pq.put(x)
count += 1
print(count)