#include <bits/stdc++.h>
using namespace std;
#define ii make_pair
const int maxN = 1e5 + 5; const int maxM = 1e7 + 5;
int n, a[maxM], connect[maxM], pre[maxM], max1, d;
long long dist;
vector < pair < int, int > > vect[maxM];
int get(int x)
{
return x == connect[x] ? x : connect[x] = get(connect[x]);
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
for (int i = 1; i <= n; i++) cin >> a[i], max1 = max(max1, a[i]);
sort(a + 1, a + 1 + n);
n = unique(a + 1, a + 1 + n) - a + 1;
for (int i = 1; i <= max1; i++) connect[i] = i;
for (int i = 1; i <= n; i++) pre[a[i]] = a[i];
for (int i = max1; i >= 1; i--) if (!pre[i]) pre[i] = pre[i + 1];
for (int i = 1; i <= n; i++)
{
int t = a[i]; int p = pre[t + 1];
if (p && p - t < t) vect[p - t].push_back(ii(t, p));
for (int j = t << 1; j <= max1; j += a[i])
{
int z = pre[j];
if (z == 0) break;
if (z - j < t) vect[z - j].push_back(ii(t, z));
}
}
for (int i = 0; i <= max1; i++)
for (auto e: vect[i])
{
int x = get(e.first); int y = get(e.second);
if (x == y) continue;
dist += i;
connect[x] = y; d++;
if (d == n - 1) break;
}
cout << dist;
}
