//g++ 2.cpp -std=c++14 -O2 -I .
#include <bits/stdc++.h>
using namespace std;

#include <atcoder/all>
using namespace atcoder;

using ll = long long;
using ld = long double;

using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vld = vector<ld>;
using vvld = vector<vld>;
using vst = vector<string>;
using vvst = vector<vst>;

#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define pq_big(T) priority_queue<T,vector<T>,less<T>>
#define pq_small(T) priority_queue<T,vector<T>,greater<T>>
#define all(a) a.begin(),a.end()
#define rep(i,start,end) for(ll i=start;i<(ll)(end);i++)
#define per(i,start,end) for(ll i=start;i>=(ll)(end);i--)
#define uniq(a) sort(all(a));a.erase(unique(all(a)),a.end())

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int n,m;
  cin>>n>>m;

  int ans=0;
  vi a(n+1,0);
  rep(i,0,m){
    int x;
    cin>>x;
    a[x]=1;
  }

  vi ok(n+1,0);
  rep(i,1,n+1){
    rep(j,1,500){
      if(j*j>i)break;
      if(i%j==0){
        ok[j]^=1;
        if(j*j!=i){
          ok[i/j]^=1;
        }
      }
    }
  }

  // 1 open
  // 0 close

  per(i,n,0){
    if(a[i]!=ok[i]){
      ans++;
      rep(j,1,500){
        if(j*j>i)break;
        if(i%j==0){
          a[j]^=1;
          if(j*j!=i){
            a[i/j]^=1;
          }
        }
      }
    }
  }

  cout<<ans<<endl;
}