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 i in range(K):
	ans += B.pop()
	
print(ans)