from collections import defaultdict, deque

def era(n):
    is_prime = [True]*(n+1)
    is_prime[0] = False
    is_prime[1] = False
    
    for i in range(2, int(n**0.5)+1):
        if not is_prime[i]:
            continue
        
        for j in range(2*i, n+1, i):
            is_prime[j] = False
    
    return [i for i in range(n+1) if is_prime[i]]
    
M = int(input())
N = int(input())
C = list(map(int, input().split()))

if M==1:
    if min(C)==1:
        print(1)
    else:
        print(0)
    exit()
    
ins = [0]*(M+1)
outs = defaultdict(list)

for i in range(M, -1, -1):
    if i!=M and ins[i]==0:
        continue
    
    for Ci in C:
        if i-Ci>=0:
            ins[i-Ci] += 1
            outs[i].append(i-Ci)

q = deque([M])
dp = [-10**18]*(M+1)
dp[M] = 0

while q:
    v = q.popleft()
    
    for nv in outs[v]:
        dp[nv] = max(dp[nv], dp[v]+1)
        ins[nv] -= 1
        
        if ins[nv]==0:
            q.append(nv)

ans = 0

for pi in era(M-1):
    if dp[pi]==-10**18:
        continue
    
    ans += dp[pi]

minC = min(C)
ans += max(dp[i] for i in range(minC) if dp[i]!=-10**18)

print(ans)