N, M = map(int,input().split())
A = list(map(int,input().split()))
B = list(map(int,input().split()))
C = list(map(int,input().split()))
C_cum = [0]
for i in range(N):
    C_cum.append(C_cum[-1]+C[i])

ans = 0
for i in range(N-1):
    if A[i+1] - A[i] == B[i%M]:
        continue
    else:
        if C_cum[i+1] <= C[i+1]:
            ans += C_cum[i+1]
        else:
            ans += C[i+1]
            A[i+1] = A[i] + B[i%M]
print(ans)