l=0
r=10**9
N=int(input())
A=list(map(int,input().split()))
B=list(map(int,input().split()))
for _ in range(60):
  m=(l+r)/2
  C=[0.00]*N
  for i in range(N):
    x=A[i]-B[i]*m
    C[i]=x
  h=[0]*(N+1)
  g=[-10**15]*(N+1)
  a=0.0
  p=[0.0]*N
  for i in range(N):
    a+=C[i]
    h[i+1]=min(h[i],a)
    p[i]=a
  a=0.0
  for i in range(N-1,-1,-1):
    g[i]=max(g[i+1],p[i])
  ans=False
  for i in range(N):
    score=g[i]-h[i]
    if score<0:
      ans=True
      break
  if ans==True:
    r=m
  else:
    l=m
print(l)