// includes #include // macros #define ll long long int #define pb emplace_back #define mk make_pair #define pq priority_queue #define FOR(i, a, b) for(int i=(a);i<(b);++i) #define rep(i, n) FOR(i, 0, n) #define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--) #define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr) #define irrep(itr, st) for(auto itr = (st).rbegin(); itr != (st).rend(); ++itr) #define vrep(v, i) for(int i = 0; i < (v).size(); i++) #define all(x) (x).begin(),(x).end() #define sz(x) ((int)(x).size()) #define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end()) #define FI first #define SE second #define dump(a, n) for(int i = 0; i < n; i++)cout << a[i] << "\n "[i + 1 != n]; #define dump2(a, n, m) for(int i = 0; i < n; i++)for(int j = 0; j < m; j++)cout << a[i][j] << "\n "[j + 1 != m]; #define bit(n) (1LL<<(n)) #define INT(n) int n; cin >> n; #define LL(n) ll n; cin >> n; #define DOUBLE(n) double n; cin >> n; using namespace std; template bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;} template bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;} template istream &operator>>(istream &is, vector &vec){for(auto &v: vec)is >> v; return is;} template ostream &operator<<(ostream &os, const vector& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;} template ostream &operator<<(ostream &os, const set& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;} template ostream &operator<<(ostream &os, const unordered_set& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;} template ostream &operator<<(ostream &os, const multiset& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;} template ostream &operator<<(ostream &os, const unordered_multiset& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;} template ostream &operator<<(ostream &os, const pair &p){os << p.first << " " << p.second; return os;} template ostream &operator<<(ostream &os, const map &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;} template ostream &operator<<(ostream &os, const unordered_map &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;} // types typedef pair P; typedef pair Pl; typedef pair Pll; typedef pair Pd; typedef complex cd; // constants const int inf = 1e9; const ll linf = 1LL << 50; const double EPS = 1e-10; const int mod = 1e9 + 7; const int dx[4] = {-1, 0, 1, 0}; const int dy[4] = {0, -1, 0, 1}; // solve template vector list_prime(T n){ vector res; vector i_prime = vector(n+1, true); for(ll i = 2; i <= n; i++){ if(i_prime[i]){ res.push_back(i); for(ll j = 2; j * i <= n; j++){ i_prime[i * j] = false; } } } return res; } template bool is_prime(T x){ if(x == 1)return false; for(ll i = 2; i * i <= x; i++){ if(x % i == 0)return false; } return true; } template map factorize(T n){ map res; T tmp = n; for(T i = 2; i * i <= n; i++){ while(tmp % i == 0){ ++res[i]; tmp /= i; } } if(tmp != 1)res[tmp] = 1; return res; } ll fi(ll n){ ll tmp = n; for(ll i = 2; i * i <= n; i++){ if(tmp % i == 0)return i; } return n; } int main(int argc, char const* argv[]) { ios_base::sync_with_stdio(false); cin.tie(0); cout << fixed << setprecision(20); LL(l); LL(h); vector p = list_prime(1e5+10); ll res = 0; for(int i = sz(p) - 1; i >= 0; i--){ for(ll j = h / p[i]; j * p[i] >= max(l, res); j--){ if(j == 1)continue; if(fi(j) >= p[i]){ res = max(res, j * p[i]); break; } } if(res > 0){ cout << res << endl; return 0; } } cout << res << endl; return 0; }