T = int(input())
N = int(input())
c = list(map(int,input().split()))
v = list(map(int,input().split()))
for i in range(N):
    x = v[i] // 2
    while x:
        c.append(c[i])
        v.append(x)
        x //= 2
N = len(v)
DP = [[0] * (T+10) for _ in range(N+10)]
for i in range(N):
    for j in range(T+1):
        DP[i+1][j] = max(DP[i][j], DP[i+1][j])
        DP[i][j+1] = max(DP[i][j], DP[i][j+1])
        if j - c[i] >= 0:
            DP[i+1][j] = max(DP[i][j-c[i]] + v[i], DP[i+1][j])
print(DP[N][T])