M = int(input())
N = int(input())
C = list(map(int, input().split()))

# Sieve of Eratosthenes to find primes up to M
def sieve(n):
    if n < 2:
        return [False] * (n + 1), []
    is_prime = [True] * (n + 1)
    is_prime[0], is_prime[1] = False, False
    for i in range(2, int(n ** 0.5) + 1):
        if is_prime[i]:
            for j in range(i * i, n + 1, i):
                is_prime[j] = False
    primes = [i for i, prime in enumerate(is_prime) if prime]
    return is_prime, primes

is_prime, primes_list = sieve(M)

# DP to compute the maximum number of cups for each sum up to M
max_num = [-1] * (M + 1)
max_num[0] = 0  # Base case: 0 money buys 0 cups

for x in range(M + 1):
    if max_num[x] == -1:
        continue
    for c in C:
        next_x = x + c
        if next_x > M:
            continue
        if max_num[next_x] < max_num[x] + 1:
            max_num[next_x] = max_num[x] + 1

# Calculate the sum of valid k_p values
sum_k = 0
for p in primes_list:
    required = M - p
    if required >= 0 and max_num[required] > 0:
        sum_k += max_num[required]

# Calculate the maximum x for the last non-reset purchase
max_x = 0
for x in range(M + 1):
    r = M - x
    if r < 0:
        continue
    if r == 0 or not is_prime[r]:
        if max_num[x] != -1 and max_num[x] > max_x:
            max_x = max_num[x]

print(sum_k + max_x)