import sys

sys.setrecursionlimit(10 ** 6)
from bisect import *
from collections import *
from heapq import *

def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def SI(): return sys.stdin.readline()[:-1]
def LLI(rows_number): return [LI() for _ in range(rows_number)]
int1 = lambda x: int(x) - 1
def MI1(): return map(int1, sys.stdin.readline().split())
def LI1(): return list(map(int1, sys.stdin.readline().split()))
p2D = lambda x: print(*x, sep="\n")
dij = [(1, 0), (0, 1), (-1, 0), (0, -1)]

def main():
    inf=10**9
    m=II()
    n=II()
    cc=LI()
    isprime=[True]*10005
    isprime[0]=isprime[1]=False
    for a in range(2,10005):
        if a**2>10005:break
        if not isprime[a]:continue
        for b in range(a*a,10005,a):
            isprime[b]=False
    dp=[-inf]*(m+1)
    dp[0]=0
    for i in range(1,m+1):
        for c in cc:
            if i-c>=0:dp[i]=max(dp[i],dp[i-c]+1)
    ans=max(dp)
    for i in range(1,m):
        if isprime[m-i] and dp[i]>0:
            ans+=dp[i]
    print(ans)

main()