#include <bits/stdc++.h>
#define FOR(i, a, b) for (auto i = (a); i <= (b); i++)
#define ROF(i, a, b) for (auto i = (a); i >= (b); i--)
using namespace std;
using ll = long long;
struct DSU {
int n, comp; vector<int> a;
DSU(int n = 0) : n(n), comp(n), a(n, -1) {}
int operator[](int x) {return find(x);}
int find(int x) {return a[x] < 0 ? x : a[x] = find(a[x]);}
int size(int x) {return -a[find(x)];}
bool same(int a, int b) {return find(a) == find(b);}
int unite(int x, int y) {
if ((x = find(x)) == (y = find(y))) return x;
if (a[x] > a[y]) swap(x, y);
return comp--, a[x] += a[y], a[y] = x;
}
};
const int N = 1e7;
int nxt[N + 1];
vector<array<int, 2>> edges[N];
void solve() {
int m, n = 0;
cin >> m;
vector<int> p(m);
for (int& i : p) {
cin >> i;
n = max(n, i);
}
sort(p.begin(), p.end());
p.erase(unique(p.begin(), p.end()), p.end());
m = p.size();
ROF(i, n, 1) {
nxt[i] = nxt[i + 1];
if (!p.empty() && i == p.back()) {
for (int j = i; j <= n; j += i) {
if (nxt[j]) {
edges[nxt[j] % i].push_back({i, nxt[j]});
}
}
nxt[i] = i;
p.pop_back();
}
}
DSU dsu(n + 1);
ll ans = 0;
FOR(i, 0, n - 1) {
for (auto [x, y] : edges[i]) {
if (!dsu.same(x, y)) {
ans += i;
dsu.unite(x, y);
}
}
}
cout << ans << "\n";
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 6/22;
}
