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

order = list(range(N))
order.sort(key=lambda i: C[i]-B[i])

ans = 0
for i in range(K):
    ans += A[order[i]] + B[order[i]]
for i in range(K,N):
    ans += A[order[i]] + C[order[i]]
print(ans)