def Eratosthenes(N): #N以下の素数のリストを返す
    N+=1
    is_prime_list = [True]*N
    m = int(N**0.5)+1
    for i in range(3,m,2):
        if is_prime_list[i]:
            is_prime_list[i*i::2*i]=[False]*((N-i*i-1)//(2*i)+1)
    return [2] + [i for i in range(3,N,2) if is_prime_list[i]]

m,n,*a = map(int,open(0).read().split())
dp = [-10**9]*(m+1)
dp[0] = 0
for ai in a:
    for i in range(ai,m+1):
        dp[i] = max(dp[i],dp[i-ai] + 1)

primes = Eratosthenes(m)
ans = 0
for i in primes:
    ans += max(0,dp[m-i])
print(ans + max(dp))