t = int(input())
n = int(input())
C = list(map(int, input().split()))
V = list(map(int, input().split()))
CV = [[C[i], V[i]] for i in range(n)]
CV.sort(key=lambda x: (x[0], x[1]))

DP = [0 for _ in range(t + 1)]
for i in range(n):
    NDP = [-1 for _ in range(t + 1)]
    c, v = CV[i]
    for j in range(t + 1):
        NDP[j] = max(NDP[j], DP[j])
        res = v
        curr = v
        for k in range(j + c, t + 1, c):
            NDP[k] = max(NDP[k], DP[j] + res)
            curr //= 2
            if curr == 0:
                break
            res += curr
    for j in range(1, t + 1):
        NDP[j] = max(NDP[j], NDP[j - 1])
    DP = NDP
print(DP[t])