T = int(input())
N = int(input())
C = list(map(int, input().split()))
V = list(map(int, input().split()))

cs = C[:]
vs = V[:]
for c, v in zip(C, V):
    v //= 2
    while v > 0:
        cs.append(c)
        vs.append(v)
        v //= 2

dp = [0] * (T+1)
for c, v in zip(cs, vs):
    for i in reversed(range(T)):
        if i+c > T: continue
        dp[i+c] = max(dp[i+c], dp[i] + v)

ans = dp[T]
print(ans)