#include <bits/stdc++.h>
//#include <chrono>
//#pragma GCC optimize("O3")
using namespace std;
#define reps(i,s,n) for(int i = s; i < n; i++)
#define rep(i,n) reps(i,0,n)
#define Rreps(i,n,e) for(int i = n - 1; i >= e; --i)
#define Rrep(i,n) Rreps(i,n,0)
#define ALL(a) a.begin(), a.end()
#define fi first
#define se second

using ll = long long;
using vec = vector<ll>;
using mat = vector<vec>;

ll N,M,H,W,Q,K,A,B;
string S;
typedef pair<ll, ll> P;
const ll INF = (1LL<<48);

int main() {
    cin>>N>>M;
    vec euler(N + 1, 1), res(N + 1, 0);
    mat prime(N + 1, vec(0));
    reps(i, 2, N+1){
        if(prime[i].empty()){
            for(int j = i; j <= N; j += i){
                prime[j].push_back(i);
            }
        }
    }
    reps(i, 1, N + 1){
        int temp(i);
        for(ll v : prime[i]){
            int k(0), tt(temp);
            while(temp%v == 0){
                temp /= v;
                ++k;
            }
            tt /= temp;
            euler[i] *= tt - tt / v;
        }
    }
    reps(i, 1, N + 1){
        for(int j = 1; j * i <= N; ++j) res[j * i] += euler[i] * j;
        res[i] -= i;
    }
    ll Res(0);
    rep(i, M){
        cin>>A;
        Res += res[A];
    }
    cout<<Res<<endl;
}