#include <bits/stdc++.h>
#pragma GCC optimize ("O3", "unroll-all-loops")
#pragma GCC target ("sse4.2")
using namespace std;
#define F first
#define S second
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define sz(a) (a).size()
#define rep(i, a, b) for (int i = (a); i < (b); ++i)
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<pii, pii> ppii;
typedef vector<int> vi;
typedef vector<ll> vll;
const long long kk = 1000;
const long long ml = kk * kk;
const long long mod = ml * kk + 7;
const long long inf = ml * ml * ml + 7;
template<class T, class U> inline istream& operator>>(istream& str, pair<T, U> &p) { return str >> p.F >> p.S; }
template<class T, class U> inline ostream& operator<<(ostream& str, const pair<T, U> &p) { str << p.F << ' ' << p.S << ' '; return str; }
template<class T> inline istream& operator>>(istream& str, vector<T> &a) { for (auto &i : a) str >> i; return str; }
template<class T> inline ostream& operator<<(ostream& str, const vector<T> &a) { for (auto &i : a) str << i << ' '; return str; }
void flush() { cout << flush; }
void flushln() { cout << endl; }
template<class T> void read(T &x) { cin >> x; }
template<class T, class ...U> void read(T &x, U&... u) { read(x); read(u...); }
template<class T> void print(const T &x) { cout << x; }
template<class T, class ...U> void print(const T &x, const U&... u) { print(x); print(u...); }
template<class ...T> void println(const T&... u) { print(u..., '\n'); }
template<class T> void eprint(const T &x) { cerr << x; }
template<class T, class ...U> void eprint(const T &x, const U&... u) { eprint(x); eprint(u...); }
template<class ...T> void eprintln(const T&... u) { eprint(u..., '\n'); }
#ifdef DEBUG
mt19937 rng(1033);
#else
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define cerr if(false)cerr
#define eprintln if(false)eprintln
#define eprint if(false)eprint
#endif
int rnd(int mod) { return uniform_int_distribution<int>(0, mod - 1)(rng); }
const int N = 500 * kk;
int n;
vector<int> v;
struct DSU {
vector<int> p;
vector<int> sz;
DSU(int n) {
p.assign(n, 0);
sz.assign(n, 1);
iota(all(p), 0);
}
int pp(int v) {
if (p[v] == v)
return v;
return p[v] = pp(p[v]);
}
bool unite(int u, int v) {
u = pp(u);
v = pp(v);
if (u == v)
return false;
if (sz[u] < sz[v])
swap(u, v);
p[u] = v;
sz[u] += sz[v];
return true;
}
};
void solve() {
cin >> n;
v.resize(n);
read(v);
set<int> s(all(v));
v.clear();
for (auto i : s)
v.push_back(i);
n = v.size();
// vector<int> where(v.back() + 1, -1);
// for (int i = 0; i < n; i++)
// where[v[i]] = i;
// vector<int> c(n);
// iota(all(c), 0);
// vector<vi> cc(n);
// for (int i = 0; i < n; i++)
// cc[c[i]].push_back(i);
const int N = v.back() + 1;
DSU dsu(N);
vi cp[N];
int ps[n];
auto fill_cp = [&]() {
for (int i = 0; i < N; i++)
cp[i].clear();
for (int i = 0; i < n; i++) {
int p = dsu.pp(v[i]);
ps[i] = p;
cp[p].push_back(v[i]);
}
};
fill_cp();
ll ans = 0;
auto unite = [&](int a, int b) {
if (!dsu.unite(a, b))
return;
ans += max(a, b) % min(a, b);
};
for (int it = 0; it < 20; it++) {
vector<int> bst(N, mod);
vector<pii> who(N, {-1, -1});
vector<pii> nxt(N, {mod, mod});
int pt = n - 1;
for (int i = N - 1; i >= 0; i--) {
if (i + 1 != N)
nxt[i] = nxt[i + 1];
if (pt != -1 && i == v[pt]) {
if (nxt[i].F != mod && ps[nxt[i].F] == ps[pt]) {
nxt[i].F = pt;
} else {
if (nxt[i].S != mod && ps[nxt[i].S] == ps[pt]) {
nxt[i].S = pt;
}
else {
nxt[i].S = pt;
}
}
pt--;
}
if (nxt[i].F > nxt[i].S)
swap(nxt[i].F, nxt[i].S);
}
for (int p = 0; p < N; p++) {
if (cp[p].empty())
continue;
// for (auto i : cp[p])
// s.erase(i);
if (true) {
for (auto i : cp[p]) {
for (int j = i; j < N; j += i) {
int lj = j;
if (lj == i)
lj++;
if (lj == N)
continue;
auto xi = nxt[lj].F;
if (xi == mod)
continue;
if (ps[xi] == p) {
continue;
// xi = nxt[j].S;
// if (xi == mod)
// continue;
}
int x = v[xi];
int lval = abs(x - j);
int px = ps[xi];
// auto px = dsu.pp(x);
if (bst[p] > lval) {
bst[p] = lval;
who[p] = {i, x};
}
if (bst[px] > lval) {
bst[px] = lval;
who[px] = {x, i};
}
// auto z = s.lower_bound(j);
// if (z != s.end()) {
// int x = *z;
// int lval = abs(x - j);
// auto px = dsu.pp(x);
// if (bst[p] > lval) {
// bst[p] = lval;
// who[p] = {i, x};
// }
// if (bst[px] > lval) {
// bst[px] = lval;
// who[px] = {x, i};
// }
// }
}
}
}
// for (auto i : cp[p])
// s.insert(i);
}
for (int p = 0; p < N; p++) {
if (who[p].F != -1) {
unite(who[p].F, who[p].S);
}
}
fill_cp();
}
println(ans);
eprintln("\n\n\n");
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cout << fixed << setprecision(20);
int t = 1;
// cin >> t;
while (t--)
solve();
#ifdef DEBUG
cerr << "Runtime is: " << clock() * 1.0 / CLOCKS_PER_SEC << endl;
#endif
}
