a,b,c,d = map(int,input().split())
z = 0
y = 0
while True:
    if a == 0:
        print(z)
        exit(0)
    a -= 1
    if b < c:
        print(z)
        exit(0)
    b -= c
    y += 1 + c 
    if y > d:
        print(z)
        exit(0)
    z += 1