#include <bits/stdc++.h>
#define ll long long
#define rep(i,m,n) for(int i=(m); i<=(n); i++)
#define reb(i,m,n) for(int i=(m); i>=(n); i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define MP make_pair
#define fs first
#define se second
#define bit(msk, i) ((msk >> i) & 1)
#define iter(id, v) for(auto id : v)
#define pb push_back
#define SZ(v) (int)v.size()
#define ALL(v) v.begin(),v.end()
using namespace std;
mt19937_64 rd(chrono :: steady_clock :: now ().time_since_epoch().count());
ll Rand (ll l, ll r) { return uniform_int_distribution<ll> (l, r) (rd); }
const int N = 1e7 + 2;
const int Mod = 1e9 + 7;
const ll INF = 2e9 + 7;
const ll BASE = 137;
const int szBL = 320;
const int N2 = 1e5 + 7;
int n, m;
int nxt[N], a[N2];
vector<pii> edges[N];
struct disjoin_set {
int lab[N2], sz[N2];
void init (int n) {
rep (i, 1, n) lab[i] = i, sz[i] = i;
}
int Find (int u) {
if (u == lab[u]) return u;
return lab[u] = Find(lab[u]);
}
bool Join (int u, int v) {
u = Find(u);
v = Find(v);
if (u == v) return 0;
if (sz[u] < sz[v]) swap(u, v);
sz[u] += sz[v];
lab[v] = u;
return 1;
}
}DSU;
void solution () {
cin >> n;
rep (i, 1, n) cin >> a[i];
sort (a + 1, a + 1 + n);
n = unique(a + 1, a + 1 + n) - a - 1;
m = *max_element(a + 1, a + 1 + n);
DSU.init(n);
rep (i, 1, n) nxt[a[i]] = i;
reb (i, m, 1) {
if (!nxt[i])
nxt[i] = nxt[i + 1];
}
rep (i, 1, n) {
if (nxt[a[i] + 1] && a[nxt[a[i] + 1]] < a[i] * 2) {
edges[a[nxt[a[i] + 1]] - a[i]].pb({i, nxt[a[i] + 1]});
}
for (int j = a[i] * 2; j <= m; j += a[i]) {
if (nxt[j] && a[nxt[j]] < j + a[i]) {
edges[a[nxt[j]] - j].pb({i, nxt[j]});
}
}
}
ll res = 0;
rep (i, 0, m) {
iter(&ed, edges[i]) if (DSU.Join(ed.fs, ed.se)) {
res += i;
}
}
cout << res <<"\n";
}
//
#define file(name) freopen(name".inp","r",stdin); \
freopen(name".out","w",stdout);
int main () {
// file("c");
ios_base :: sync_with_stdio(false); cin.tie(0); cout.tie(0);
int num_Test = 1;
// cin >> num_Test;
while (num_Test--)
solution();
}
/*
no bug challenge +2
2 + 8 * 2 - 9
7 7
0 2 5
0 1 1
2 1 2
2 2 1
4 4 1
4 6 2
6 3 3
*/
