#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr ll LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
constexpr int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  }
} iosetup;

std::vector<int> euler_phi_init(int val) {
  std::vector<int> phi(val + 1);
  for (int i = 0; i <= val; ++i) phi[i] = i;
  for (int i = 2; i <= val; ++i) {
    if (phi[i] == i) {
      for (int j = i; j <= val; j += i) phi[j] -= phi[j] / i;
    }
  }
  return phi;
}

int main() {
  int n, m; cin >> n >> m;
  // https://oeis.org/A006579
  vector<int> phi = euler_phi_init(n);
  vector<ll> s(n + 1, 0);
  FOR(i, 2, n + 1) for (int j = i; j <= n; j += i) s[j] += 1LL * (i - 1) * phi[j / i];
  // REP(a, n + 1) {
  //   ll sum = 0;
  //   FOR(b, 1, a + 1) {
  //     int mn = a - 1, y = (a - 1 - b + a) % a;
  //     while (y != a - 1) {
  //       chmin(mn, y);
  //       y = (y - b + a) % a;
  //     }
  //     sum += mn;
  //   }
  //   cout << sum << " \n"[a == n];
  // }
  ll ans = 0;
  while (m--) {
    int a; cin >> a;
    ans += s[a];
  }
  cout << ans << '\n';
  return 0;
}