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(C)
for i in range(N):
  B[i] -= C[i]
B.sort()
for k in range(K):
  ans += B.pop()
print(ans)