T = int(input())
N = int(input())
C = list(map(int, input().split()))
V = list(map(int, input().split()))
dp = [0] * 20000

for i in range(N):
    while V[i] > 0:
        for j in range(T - 1, -1, -1):
            dp[j + C[i]] = max(dp[j + C[i]], dp[j] + V[i])

        V[i] = V[i] // 2

ans = 0
for i in range(T + 1):
    ans = max(ans, dp[i])

print(ans)