if __name__=='__main__':

    n,m = map(int,input().split())
    p = list(map(int,input().split()))

    res = 0
    for i in range(1,1<<m):
        t, cnt = 1, 0
        for j in range(m):
            if i >> j & 1:
                cnt += 1
                if t * p[j] > n:
                    t = -1
                    break
                t *= p[j]

        if t != -1:
            if cnt % 2 :
                res += n // t
            else:
                res -= n // t

    print(res)