#include <bits/stdc++.h>
using namespace std;
struct DisjointSets {
vector<int> e;
DisjointSets(int n): e(n, -1) { }
int find(int x) {
return e[x] < 0 ? x : e[x] = find(e[x]);
}
bool unite(int a, int b) {
a = find(a); b = find(b);
if (a == b) return false;
if (-e[a] > -e[b]) swap(a,b);
e[b] += e[a];
e[a] = b;
return true;
}
bool connected(int a, int b) {
return find(a) == find(b);
}
};
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<int> a(n);
for(int &x : a) cin >> x;
sort(a.begin(), a.end());
a.erase(unique(a.begin(), a.end()), a.end());
n = (int)a.size();
int M = a.back();
vector<int> nxt(M+2, 0);
vector<vector<pair<int,int>>> edges(M+1);
for(int i = 0; i < n; i++){
nxt[a[i]] = -(i+1);
}
for(int i = M-1; i >= 0; i--){
if(nxt[i] == 0){
nxt[i] = nxt[i+1];
}
if (nxt[i] < 0) nxt[i] = -nxt[i];
}
for(int i = 0; i < n-1; i++){
int ai = a[i];
for(int j = ai; j <= M; j += ai){
int idx = nxt[j];
if (idx == 0) break;
int at = a[idx - 1];
int diff = at - j;
if (diff < 0 || at >= ai + j)
continue;
edges[diff].emplace_back(i+1, idx);
}
}
DisjointSets dsu(n);
long long ans = 0;
for(int cost = 0; cost <= M; cost++){
for(auto &e : edges[cost]){
int u = e.first - 1;
int v = e.second - 1;
if (!dsu.connected(u, v)){
dsu.unite(u, v);
ans += cost;
}
}
}
cout << ans << endl;
}
