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

dp = [0]*(T+1)
for c,v in zip(C,V):
    for i in range(10):
        for t in range(T+1)[::-1]:
            if c+t <= T:
                dp[c+t] = max(dp[c+t],dp[t]+v)
        v //= 2
print(dp[-1])