from heapq import *

def f(x, y):
    return x * (N + 1) + y
def g(v):
    return v // (N + 1), v % (N + 1)

N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
B = B + B
ans = 10 ** 18
for i in range(N):
    H = []
    for j in range(N):
        heappush(H, f(A[j], 0))
        
    for j in range(i, i + N):
        nx, ny = g(heappop(H))
        ny += 1
        nx += B[j]//2
        heappush(H, f(nx, ny))
    temp = 0
    for v in H:
        x, y = g(v)
        temp = max(temp, y)
    ans = min(ans, temp)
    
print(ans)