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

ans = sum(A) + sum(B)
data = list(map(lambda x: x[1] - x[0], zip(B, C)))
data.sort()
for _ in range(N - K):
    ans += data.pop()
print(ans)