N, K = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))

# DP[0][0] = A[0] + C[0]  # 0本目をタレ


# print(f"{DP=}")

# for k in range(1, K + 1):
#     for n in range(1, N):
#         # print(f"{k=}, {n=}")

#         tare = (DP[k][n - 1] + A[n] + C[n]) if DP[k][n - 1] != 0 else 0
#         sio = (DP[k - 1][n - 1] + A[n] + B[n]) if DP[k - 1][n - 1] != 0 else 0

#         # print(f"{A + C[n]=}, {tare=}")
#         # print(f"{A + B[n]=}, {sio=}")

#         DP[k][n] = max(tare, sio)

# print(f"{DP=}")

# print(DP[K][N - 1])


TARE = [0] * N
TARE[0] = A[0] + C[0]  # 0本目をタレ

# 全部タレ使用の初期値
for i in range(1, N):
    TARE[i] = TARE[i - 1] + (A[i] + C[i])

# print(f"{TARE=}")


SIO = [0] * N
SIO[0] = A[0] + B[0]  # 0本目を塩

# print(f"{SIO=}")

for k in range(1, K + 1):
    for n in range(1, N):
        # print(f"{k=}, {n=}")

        n_is_tare = (SIO[n - 1] + A[n] + C[n]) if SIO[n - 1] != 0 else 0
        n_is_sio = (TARE[n - 1] + A[n] + B[n]) if TARE[n - 1] != 0 else 0

        # print(f"{A[n] + C[n]=}, {n_is_tare=}")
        # print(f"{A[n] + B[n]=}, {n_is_sio=}")

        SIO[n] = max(n_is_sio, n_is_tare)

    # print(f"{TARE=}")
    # print(f"{SIO=}")
    if k == K:
        break
    else:
        # 繰り上げ
        TARE = SIO.copy()
        SIO = [0] * N


# print(f"{SIO=}")

print(SIO[-1])