#!/usr/bin/env PyPy3

from collections import Counter, defaultdict, deque
import itertools
import re
import math
from functools import reduce
import operator
import bisect
from heapq import *
import functools
mod=998244353

import sys
input=sys.stdin.readline
n,m=map(int,input().split())
a=list(map(int,input().split()))

open = [0] * (n+1)
div = [[] for _ in range(n+1)]
for i in range(1,n+1):
    for j in range(i,n+1,i):
        div[j].append(i)
for i in range(1,n+1):
    if (n // i) % 2:
        open[i] = 1

fact = [0] * (n+1)
for aa in a:
    fact[aa] = 1
ans = 0
for i in range(1,n+1)[::-1]:
    if fact[i] != open[i]:
        ans += 1
        for j in div[i]:
            open[j] ^= 1
print(ans)