IsPrime = [True for _ in range(10**4 + 1)]
IsPrime[0] = IsPrime[1] = False
for i in range(2, 10**4 + 1):
    if IsPrime[i]:
        for j in range(i * i, 10**4 + 1, i):
            IsPrime[j] = False

c = int(input())
n = int(input())
C = list(map(int, input().split()))

DP = [-1 for _ in range(c + 1)]
DP[c] = 0
for i in range(n):
    a = C[i]
    for j in range(c, -1, -1):
        if DP[j] != -1 and j - a >= 0:
            DP[j - a] = max(DP[j - a], DP[j] + 1)
ans = max(DP)
for i in range(c + 1):
    if IsPrime[i] and DP[i] != -1:
        ans += DP[i]
print(ans)