N,K = map(int,input().split())
A = list(map(int,input().split()))
ans = sum(A)
B = list(map(int,input().split()))
C = list(map(int,input().split()))
l = [(B[i] - C[i],i) for i in range(N)]
l.sort()
for j in range(K):
	u,i = l[j]
	ans += B[i]
for j in range(K + 1,N):
	u,i = l[j]
	ans += C[i]
print(ans)