#include<bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define f first
#define s second
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pb push_back
#define epb emplace_back
using namespace std;
void lastshot(){
cout << "FUCK THIS SHIT I'M OUT!\n";
}
void debug(){
cout << "WHAT A STUPID\n";
}
//WELCOME TO PROJECT MAYHEM
// rule #1: You don't ask questions about project MAYHEM
// rule #2: You don't ask questions about project MAYHEM
const int PMAX = 1e7 + 5;
const int NMAX = 2e5 + 1;
int p[PMAX];
int last[PMAX];
vector <vector <int> > g(NMAX);
vector <int>par(NMAX);
vector <int> sz(NMAX);
void make_set(int v){
par[v] = v;
sz[v] = 1;
}
int find_set(int v){
return par[v] == v ? v : par[v] = find_set(par[v]);
}
void union_sets(int a, int b){
a = find_set(a);
b = find_set(b);
if(a != b){
if(sz[a] < sz[b]) swap(a, b);
par[b] = a;
sz[a] += sz[b];
}
}
int main(){
int n; cin >> n;
set <int> st;
for(int i = 1; i <= n; i++){
int x; cin >> x;
st.insert(x);
}
int ind = 0;
for(int to : st){
p[to] = ++ind;
}
int l = 10000001;
for(int i = 10000001; i >= 1; i--){
if(p[i]) last[i] = i, l = i;
else last[i] = l;
}
// cout << 1;
ind = 1;
vector <pair <ll, pii> > edges;
for(int to : st){
int x = last[to + 1];
if(x < 2 * to && x < 1e7 + 1)
edges.pb({x - to, {ind, p[x]}});
for(int i = 2 * to; i <= 1e7; i += to){
x = last[i];
if(x > 1e7) break;
if(x > 1e7 || x >= i + to) continue;
edges.pb({x - i, {p[x], ind}});
}
ind++;
}
//cout << 1;
for(int i = 1; i < ind; i++){
make_set(i);
}
sort(edges.begin(), edges.end());
ll sum = 0;
for(auto to : edges){
// cout << to.f << ' ' << to.s.f << ' ' << to.s.s << "\n";
int x = to.s.f, y = to.s.s;
if(find_set(x) == find_set(y)) continue;
union_sets(x, y);
sum += to.f;
}
cout << sum;
return 0;
}
