s = 0
e = 1000000000
ans = 0
n, l, w, h = map(int, input().split())
for i in range(100000):
mid = (s + e) / 2
cnt = ((l / mid) // 1) * ((w / mid) // 1) * ((h / mid) // 1)
if cnt >= n:
ans = max(ans, mid)
s = mid + 0.000000001
else:
e = mid - 0.000000001
print(ans)