#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
template<class A, class B> bool maximize(A& x, B y) {if (x<y) return x = y, true; else return false;}
template<class A, class B> bool minimize(A& x, B y) {if (x>y) return x = y, true; else return false;}
const int maxn = 1e5 + 5;
const int max_edges_size = 3e7 + 9;
const int maxval = 1e7 + 5;
int n;
int ma;
vector<int> a;
pair<pair<int, int>, int> edges[max_edges_size], sorted_edges[max_edges_size];
int par[maxn], sz[maxn];
int nxt[maxval], cnt[maxval];
int root (int u) {
return ((par[u] == u) ? u : (par[u] = root(par[u])) );
}
bool join (int u, int v) {
u = root(u);
v = root(v);
if (u == v)
return false;
if (sz[u] < sz[v])
swap (u, v);
par[v] = u;
sz[u] += sz[v];
return true;
}
void countingSortEdges(int m) {
if (m <= 0) {
return;
}
for (int i = 1; i <= m; ++i) {
cnt[edges[i].second]++;
}
for (int i = 1; i <= ma; ++i) {
cnt[i] += cnt[i - 1];
}
int key, post_pos;
for (int i = m; i >= 1; --i) {
key = edges[i].second;
post_pos = cnt[key];
sorted_edges[post_pos] = edges[i];
cnt[key]--;
}
for (int i = 1; i <= m; ++i) {
edges[i] = sorted_edges[i];
}
}
signed main () {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin >> n;
a.resize(n);
ma = 0;
for (int i = 0; i < n; ++i) {
cin >> a[i];
maximize(ma, a[i]);
}
fill_n (&nxt[0], maxval, -1);
sort (a.begin(), a.end());
a.erase(unique(a.begin(), a.end()), a.end());
n = a.size();
for (int i = 0; i < n; ++i) {
nxt[a[i]] = i;
par[i] = i;
sz[i] = 1;
}
for (int i = ma; i >= 0; --i)
if (nxt[i] == -1)
nxt[i] = nxt[i + 1];
int u, w, minw;
int pre = -1;
int m = 0;
for (int i = 0; i < a.size(); ++i) {
minw = 1e7;
for (int k = 0; k * a[i] <= ma; ++k) {
u = nxt[k * a[i] + (k == 1)];
if (u != -1 && u != pre) {
w = min(a[i] % a[u], a[u] % a[i]);
if (w < minw) {
edges[++m] = (pair<pair<int, int>, int>(pair<int, int>(i, u), w));
minw = w;
}
// cout << i << ' ' << u << ' ' << w << '\n';
pre = u;
}
}
}
countingSortEdges(m);
int v;
long long ans = 0;
for (int i = 1; i <= m; ++i) {
const pair<pair<int, int>, int>& edge = edges[i];
u = edge.first.first;
v = edge.first.second;
w = edge.second;
ans += (long long)w * (long long)join(u, v);
}
cout << ans;
return 0;
}
