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

# SIO = [A[i] + B[i] for i in range(N)]
# TARE = [A[i] + C[i] for i in range(N)]

DP = [[0] * N for _ in range(K + 1)]  # 初期値、列数、行数
# DP[使用塩数(max = K-1)][n本目(max = N-1)]


DP[0][0] = A[0] + C[0]  # 0本目をタレ
DP[1][0] = A[0] + B[0]  # 0本目を塩

# print(f"{A + C=}")
# print(f"{A + B=}")

# 全部タレ使用の初期値
for i in range(1, N):
    DP[0][i] = DP[0][i - 1] + (A[i] + C[i])

# 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])