import sys
import heapq

input = sys.stdin.readline


def main():
    N = int(input())
    *A, = map(int, input().split())
    *B, = map(int, input().split())

    ans = N

    initQ = [(a, 0) for a in A]
    heapq.heapify(initQ)

    for i in range(N):
        Q = initQ[:]
        for j in range(i, N+i):
            if j >= N:
                j -= N

            lv, bt = Q[0]
            heapq.heapreplace(Q, (lv+B[j]//2, bt+1))

        ans = min(ans, max((bt for lv, bt in Q)))

    print(ans)


if __name__ == '__main__':
    main()