#pragma GCC optimize ("O3")
#include <bits/stdc++.h>

// clang-format off
using namespace std;
using ll = long long int;

#define all(v) (v).begin(),(v).end()
#define repeat(cnt,l) for(typename remove_const<typename remove_reference<decltype(l)>::type>::type cnt={};(cnt)<(l);++(cnt))
#define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt))
#define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt))
#define increase(cnt,b,e) for(auto cnt=(b);(cnt)<(e);++(cnt))
#define decrease(cnt,b,e) for(auto cnt=(b);(e)<=(cnt);--(cnt))
const long long MD = 1000000007; const long double PI = 3.1415926535897932384626433832795L;
template<typename T1, typename T2> inline ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << '(' << p.first << ':' << p.second << ')'; return o; }
template<typename T> inline T& chmax(T& to, const T& val) { return to = max(to, val); }
template<typename T> inline T& chmin(T& to, const T& val) { return to = min(to, val); }
void bye(string s, int code = 0) { cout << s << endl; exit(code); }
mt19937_64 randdev(8901016);
template<typename T, typename Random = decltype(randdev), typename enable_if<is_integral<T>::value>::type* = nullptr>
inline T rand(T l, T h, Random& rand = randdev) { return uniform_int_distribution<T>(l, h)(rand); }
template<typename T, typename Random = decltype(randdev), typename enable_if<is_floating_point<T>::value>::type* = nullptr>
inline T rand(T l, T h, Random& rand = randdev) { return uniform_real_distribution<T>(l, h)(rand); }template<typename T>
static ostream& operator<<(ostream& o, const std::vector<T>& v) {
  o << "[ "; for(const auto& e : v) o<<e<<' '; return o << ']';
}

template <typename I> struct MyRangeFormat{ I b,e; MyRangeFormat(I _b, I _e):b(_b),e(_e){} };
template<typename I> static ostream& operator<<(ostream& o, const MyRangeFormat<I>& f) {
  o << "[ "; iterate(i,f.b,f.e) o<<*i<<' '; return o << ']';
}
template <typename I> struct MyMatrixFormat{
  const I& p; long long n, m;
  MyMatrixFormat(const I& _p, long long _n, long long _m):p(_p),n(_n),m(_m){}
};
template<typename I> static ostream& operator<<(ostream& o, const MyMatrixFormat<I>& f) {
  o<<'\n';
  repeat(i,(f.n)) {
    repeat(j,f.m) o<<f.p[i][j]<<' ';
    o<<'\n';
  }
  return o;
}
struct LOG_t { ~LOG_t() { cout << endl; } };
#define LOG (LOG_t(),cout<<'L'<<__LINE__<<": ")
#define FMTA(m,w) (MyRangeFormat<decltype(m+0)>(m,m+w))
#define FMTR(b,e) (MyRangeFormat<decltype(e)>(b,e))
#define FMTV(v) FMTR(v.begin(),v.end())
#define FMTM(m,h,w) (MyMatrixFormat<decltype(m+0)>(m,h,w))

#if defined(_WIN32) || defined(_WIN64)
#define getc_x _getc_nolock
#define putc_x _putc_nolock
#elif defined(__GNUC__)
#define getc_x getc_unlocked
#define putc_x putc_unlocked
#else
#define getc_x getc
#define putc_x putc
#endif
class MaiScanner {
  FILE* fp_;
  constexpr bool isvisiblechar(char c) noexcept { return (0x21<=(c)&&(c)<=0x7E); }
public:
  inline MaiScanner(FILE* fp):fp_(fp){}
  template<typename T> void input_integer(T& var) noexcept {
    var = 0; T sign = 1;
    int cc = getc_x(fp_);
    for (; cc < '0' || '9' < cc; cc = getc_x(fp_))
      if (cc == '-') sign = -1;
    for (; '0' <= cc && cc <= '9'; cc = getc_x(fp_))
      var = (var << 3) + (var << 1) + cc - '0';
    var = var * sign;
  }
  inline int c() noexcept { return getc_x(fp_); }
  template<typename T, typename enable_if<is_integral<T>::value, nullptr_t>::type = nullptr>
  inline MaiScanner& operator>>(T& var) noexcept { input_integer<T>(var); return *this; }
  inline MaiScanner& operator>>(string& var) {
    int cc = getc_x(fp_);
    for (; !isvisiblechar(cc); cc = getc_x(fp_));
    for (; isvisiblechar(cc); cc = getc_x(fp_))
      var.push_back(cc);
    return *this;
  }
  template<typename IT> inline void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; }
};
class MaiPrinter {
  FILE* fp_;
public:
  inline MaiPrinter(FILE* fp):fp_(fp){}
  template<typename T>
  void output_integer(T var) noexcept {
    if (var == 0) { putc_x('0', fp_); return; }
    if (var < 0)
      putc_x('-', fp_),
      var = -var;
    char stack[32]; int stack_p = 0;
    while (var)
      stack[stack_p++] = '0' + (var % 10),
      var /= 10;
    while (stack_p)
      putc_x(stack[--stack_p], fp_);
  }
  inline MaiPrinter& operator<<(char c) noexcept { putc_x(c, fp_); return *this; }
  template<typename T, typename enable_if<is_integral<T>::value, nullptr_t>::type = nullptr>
  inline MaiPrinter& operator<<(T var) noexcept { output_integer<T>(var); return *this; }
  inline MaiPrinter& operator<<(const char* str_p) noexcept { while (*str_p) putc_x(*(str_p++), fp_); return *this; }
  inline MaiPrinter& operator<<(const string& str) {
    const char* p = str.c_str();
    const char* l = p + str.size();
    while (p < l) putc_x(*p++, fp_);
    return *this;
  }
  template<typename IT> void join(IT begin, IT end, char sep = ' ') { for (bool b = 0; begin != end; ++begin, b = 1) b ? *this << sep << *begin : *this << *begin; }
};
MaiScanner scanner(stdin);
MaiPrinter printer(stdout);
// clang-format on

// template <int Max = 2000>
template <int Max>
class Prime {
  int d_[Max + 1];
  int n_;
  int li_[std::max(10000, Max / 10)];

 public:
  constexpr Prime() : d_(), n_(), li_() {
    d_[0] = d_[1] = 0;
    for (int i = 2; i <= Max; i += 2) {
      d_[i] = 2;
    }
    n_ = 1;
    li_[0] = 2;
    int p = 3;
    for (p = 3; p * p <= Max; p += 2) {
      if (d_[p] != 0)
        continue;
      d_[p] = p;
      li_[n_++] = p;
      for (int j = p * p; j <= Max; j += p) {  // i*i
        d_[j] = p;
      }
    }
    for (; p <= Max; p += 2) {
      if (d_[p] != 0)
        continue;
      d_[p] = p;
      li_[n_++] = p;
    }
  }
  constexpr inline bool isPrime(int x) const { return (x >= 2) && (x == 2 || d_[x] == x); }
  constexpr inline int size() const { return n_; }
  constexpr inline int operator[](int i) const { return li_[i]; }

  class iterator {
    const Prime& pl;
    int ptr = 0;

   public:
    constexpr iterator(const decltype(pl)& _pl, int _ptr = 0) : pl(_pl), ptr(_ptr) {}
    constexpr int operator*() const { return pl[ptr]; }
    constexpr iterator& operator++() {
      ptr++;
      return *this;
    }  // prefix
    constexpr inline bool operator!=(const iterator& it) const {
      return ptr != it.ptr ? !(pl.n_ <= ptr && pl.n_ <= it.ptr) : false;
    }
    constexpr inline bool operator==(const iterator& it) const {
      return ptr != it.ptr ? (pl.n_ <= ptr && pl.n_ <= it.ptr) : true;
    }
  };
  constexpr Prime::iterator begin() const { return Prime::iterator(*this, 0); }
  constexpr Prime::iterator end() const { return Prime::iterator(*this, n_); }

  std::map<int, int> division(long long number) const {
    std::map<int, int> div;
    // for large number
    for (int i = 0; (long long)Max <= number && i < n_; ++i) {
      long long p = li_[i];
      int c = 0;
      while (number / p * p == number)
        ++c, number /= p;
      if (c > 0)
        div[(int)p] = c;
    }
    if ((long long)Max <= number) {
      // guess it's prime number.
      div[number] += 1;
      return div;
    }
    while (number >= 2) {
      long long p = d_[number];
      int c = 0;
      while (number / p * p == number)
        ++c, number /= p;
      if (c > 0)
        div[(int)p] = c;
    }
    return div;
  }
};


//

// sqrt(10**10) = 10**5 より大きな素数を見る必要は無い。
// 調べたいのは合成数。
// H 以下の合成数に sqrt(H) を超える素数を素因数に持つ可能性はあるが、
// その場合は、常に sqrt(H) 未満の素数を必ず素因数に持つ。
// よって、高々 sqrt(H) までの素数を予め列挙しておけば十分である。
constexpr int kMaxPrime = 101010;
Prime<kMaxPrime> prime;

ll L, H;

//

int main() {
  
  cin >> L >> H;
  
  pair<ll, ll> best(0, 0);  // < 素因数, 値>
  rrepeat(pi, prime.size()) {
    ll p = prime[pi];
    // H 以下の値だけを見たいので、H < p な素数は興味がない。
    // H == p ならば、H は素数なので、H は解から除外出来る
    if (H <= p)
      continue;
    
    // H 以下かつ、p の倍数を満たす最大値を求める。最大以外の値は興味が無い。
    ll h = H/p*p;
    // L 未満なら制約違反の値なので除く。
    if (h < L) continue;
    // 素数は対象外
    if (h == p) continue;
    
    // p は h の最小の素因数とは限らないので、最小の素因数を求めよう
    // TODO: この部分のならし計算量が不明。2や3等の小さな素数のヒット率が高いので、
    // O(n/logn)より確実に小さくなる。
    ll minp = p;
    for (ll p2 : prime) {
      if (h/p2*p2 == h) {
        chmin(minp, p2);
        break;
      }
    }
    chmax(best, pair<ll,ll>(minp, h));
  }
  
  cout << best.second << endl;
  
  return 0;
}