#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define ll long long
const ll N = 2e5 + 5;
const ll M = 1e7 + 5;
ll p[N+1] = {};
ll sz[N+1] = {};
ll find(ll a){
if(a == p[a]) return a;
return p[a] = find(p[a]);
}
void unite(ll a, ll b){
if(a != b){
if(sz[a] < sz[b]) swap(a, b);
p[b] = a;
if(sz[a] == sz[b]) sz[a]++;
}
}
int main() {
ll n;
cin>>n;
vector<ll> v(n);
ll close[M] = {};
ll index[M] = {};
ll mas[M] = {};
memset(index, -1, sizeof index);
for(ll i = 0; i < n; i++){
p[i] = i;
sz[i] = 0;
cin>>v[i];
close[v[i]] = v[i];
if(index[v[i]] == -1) index[v[i]] = i;
}
for(ll i = M-2; i >= 0; i--){
if(!close[i]) close[i] = close[i+1];
}
vector<vector<pair<ll, ll> > > e(M);
for(ll i = 0; i < n; i++){
if(mas[v[i]]++) continue;
if(close[v[i]+1]){
if(2*v[i] >= M || close[2*v[i]] != close[v[i]+1]){
e[close[v[i]+1] - v[i]].push_back({i, index[close[v[i]+1]]});
}
}
for(ll j = 2*v[i]; j < M && close[j]; j+=v[i]){
ll x = close[j];
if(j+v[i] >= M || close[j+v[i]] != x){
e[x - j].push_back({i, index[x]});
}
}
}
ll ans = 0;
for(ll i = 0; i < M; i++){
for(ll j = 0; j < e[i].size(); j++){
ll a = find(e[i][j].f);
ll b = find(e[i][j].s);
if(a != b){
unite(a,b);
ans += i;
}
}
}
cout<<ans;
return 0;
}
