import sys
read=sys.stdin.buffer.read
readline=sys.stdin.buffer.readline
readlines=sys.stdin.buffer.readlines

t=int(readline())
n=int(readline())
c=list(map(int, readline().split()))
v=list(map(int, readline().split()))
dp=[0]*(t+1)
for x, y in zip(c, v):
    while y:
        for i in range(t-x, -1, -1):
            dp[i+x]=max(dp[i+x], dp[i]+y)
        y>>=1
print(dp[t])