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