#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define elif else if
#define sp(x) fixed << setprecision(x)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
//const int MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
const double pi = acos(-1.0);
const double EPS = 1e-10;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

int main(){
    int N, M;
    cin >> N >> M;
    int A[M];
    rep(i, M) cin >> A[i];

    int p[N+1];
    fill(p, p+N+1, -1);
    rep2(i, 2, N+1){
        if(p[i] != -1) continue;
        for(int j = i; j <= N; j += i){
            if(p[j] == -1) p[j] = i;
        }
    }
    ll dp[N+1];
    dp[1] = 1;
    rep2(i, 2, N){
        int j = p[i], k = 1, tmp = i;
        while(tmp%j == 0) tmp /= j, k *= j;
        dp[i] = (k-k/j)*dp[i/k]+j*dp[i/j];
    }

    ll ans = 0;
    rep(i, M){
        ans += dp[A[i]]-A[i];
    }
    cout << ans << endl;
}