#include <bits/stdc++.h>
using namespace std;
//#define int long long
#define endl "\n"
#define pb push_back
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const int N = 1e7 + 5;
int exist[N],con[N],par[N],sz[N];
struct node{
int a,b,c;
bool operator < (const node other) const{
return c < other.c;
};
};
struct DSU{
int find(int x){
if(x == par[x]) return x;
return par[x] = find(par[x]);
}
void unite(int a,int b){
a = find(a),b = find(b);
if(sz[a] < sz[b]) swap(a,b);
sz[a] += sz[b];
par[b] = a;
sz[b] = 0;
}
};
void solve(){
int n;
cin >> n;
vector<int> v(n);
for(int i = 0; i < n; i++){
cin >> v[i];
}
sort(all(v)); v.resize(unique(all(v)) - v.begin());
for(int x : v){
exist[x] = 1;
}
DSU dsu;
for(int i = N - 2; i >= 1; i--){
con[i] = (exist[i] ? i : con[i + 1]);
par[i] = i,sz[i] = 1;
}
vector<node> edges;
for(int x : v){
edges.pb({x,con[x+1],con[x+1] % x});
for(int j = x*2; j < N; j += x){
if(!con[j] || con[j] >= j + x) continue;
edges.pb({x,con[j],con[j] % x});
}
}
sort(all(edges)); long long ans = 0;
for(auto[a,b,c] : edges){
if(dsu.find(a) != dsu.find(b)){
dsu.unite(a,b), ans += c;
}
}
cout << ans << endl;
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
while(t--)
solve();
return 0;
}
