#include <bits/stdc++.h>
using namespace std;
const char el = '\n';
typedef long long ll;
const ll inf = 1e18;
ll first(ll l, ll i, ll r, ll d) {
  l += (d - l % d) % d;
  if (l <= r && l != i) return l * i / d;
  return inf;
}
struct edge {
  ll u, v;
  ll w;
};
struct dsu {
  vector<int> f;
  dsu(int n) : f(n + 1, -1) {}
  int ff(int u) { return ~f[u] ? f[u] = ff(f[u]) : u; }
  void conn(int u, int v) {
    u = ff(u), v = ff(v);
    if (u != v) f[u] = v;
  }
};
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << setprecision(15);
  ll l, r;
  cin >> l >> r;
  ll ans = 0;
  vector<edge> a;
  for (int i = 1; i <= r; i++) {
    ll s = l + (i - l % i) % i;
    for (ll t = s + i; t <= r; t += i) a.push_back({s, t, s * t / i});
  }
  sort(a.begin(), a.end(), [](edge a, edge b) { return a.w < b.w; });
  dsu d(r);
  for (auto [u, v, w] : a)
    if (d.ff(u) != d.ff(v)) {
      ans += w;
      d.conn(u, v);
    }
  cout << ans << el;
  return 0;
}