INF = 10**18

N = int(input())
A = [int(s) for s in input().split()]
B = [int(s) for s in input().split()]
C = [int(s) for s in input().split()]


def calc_dp(adder):
    dp = [[-INF] * 5 for _ in range(N + 1)]
    dp[0][0] = 0

    for i in range(N):
        for j in range(5):
            dp[i + 1][j] = max(dp[i][: j + 1]) + adder[j][i]

    return max(dp[N])


result_not_intersect = calc_dp([A, B, A, B, A])
result_intersect = calc_dp([A, B, C, B, A])

print(max(result_not_intersect, result_intersect))