import sys

def main():
    T = int(sys.stdin.readline())
    N = int(sys.stdin.readline())
    c = list(map(int, sys.stdin.readline().split()))
    v = list(map(int, sys.stdin.readline().split()))
    
    attractions = []
    
    for i in range(N):
        current_c = c[i]
        current_v = v[i]
        options = [(0, 0)]
        current_time = current_c
        total_value = current_v
        if current_time <= T:
            options.append((current_time, total_value))
        next_v = current_v // 2
        while next_v > 0 and current_time + current_c <= T:
            current_time += current_c
            total_value += next_v
            options.append((current_time, total_value))
            next_v = next_v // 2
        
        sorted_options = sorted(options, key=lambda x: x[0])
        pruned = []
        max_val = -1
        for t, val in sorted_options:
            if val > max_val:
                pruned.append((t, val))
                max_val = val
        attractions.append(pruned)
    
    dp_prev = [-1] * (T + 1)
    dp_prev[0] = 0
    
    for attraction in attractions:
        new_dp = [x for x in dp_prev]
        for t_opt, val_opt in attraction:
            for t in range(T, t_opt - 1, -1):
                if dp_prev[t - t_opt] != -1:
                    if new_dp[t] < dp_prev[t - t_opt] + val_opt:
                        new_dp[t] = dp_prev[t - t_opt] + val_opt
        dp_prev = new_dp
    
    max_val = max([v for v in dp_prev if v != -1])
    print(max_val)

if __name__ == "__main__":
    main()