//#define NDEBUG
#include <cstddef>
#include <cstdint>
#include <iostream>
#include <iterator>
#include <vector>

namespace n91 {

  using i8 = std::int_fast8_t;
  using i32 = std::int_fast32_t;
  using i64 = std::int_fast64_t;
  using u8 = std::uint_fast8_t;
  using u32 = std::uint_fast32_t;
  using u64 = std::uint_fast64_t;
  using isize = std::ptrdiff_t;
  using usize = std::size_t;

  constexpr usize operator"" _z(unsigned long long x) noexcept {
    return static_cast<usize>(x);
  }

  template <class T> class integral_iterator {
  public:
    using difference_type = T;
    using value_type = T;
    using pointer = const value_type*;
    using reference = value_type;
    using iterator_category = std::random_access_iterator_tag;

  private:
    using self_type = integral_iterator<value_type>;
    value_type i;

  public:
    constexpr integral_iterator() noexcept : i() {}
    explicit constexpr integral_iterator(const value_type i) noexcept : i(i) {}
    constexpr self_type operator++(int) noexcept { return self_type(i++); }
    constexpr self_type operator--(int) noexcept { return self_type(i--); }
    constexpr self_type operator[](const difference_type rhs) const noexcept {
      return self_type(i + rhs);
    }
    constexpr self_type& operator++() noexcept {
      ++i;
      return *this;
    }
    constexpr self_type& operator--() noexcept {
      --i;
      return *this;
    }
    constexpr reference operator*() const noexcept { return i; }
    constexpr self_type operator+(const difference_type rhs) const noexcept {
      return self_type(i + rhs);
    }
    constexpr self_type operator-(const difference_type rhs) const noexcept {
      return self_type(i - rhs);
    }
    constexpr difference_type operator-(const self_type rhs) const noexcept {
      return i - rhs.i;
    }
    constexpr bool operator<(const self_type rhs) const noexcept {
      return i < rhs.i;
    }
    constexpr bool operator<=(const self_type rhs) const noexcept {
      return i <= rhs.i;
    }
    constexpr bool operator>(const self_type rhs) const noexcept {
      return i > rhs.i;
    }
    constexpr bool operator>=(const self_type rhs) const noexcept {
      return i >= rhs.i;
    }
    constexpr bool operator==(const self_type rhs) const noexcept {
      return i == rhs.i;
    }
    constexpr bool operator!=(const self_type rhs) const noexcept {
      return i != rhs.i;
    }
    constexpr self_type& operator+=(const difference_type rhs) noexcept {
      i += rhs;
      return *this;
    }
    constexpr self_type& operator-=(const difference_type rhs) noexcept {
      i -= rhs;
      return *this;
    }
  };
  template <class T>
  constexpr integral_iterator<T> make_int_itr(const T i) noexcept {
    return integral_iterator<T>(i);
  }
  class rep {
    const usize f, l;

  public:
    constexpr rep(const usize f, const usize l) noexcept : f(f), l(l) {}
    constexpr auto begin() const noexcept { return make_int_itr(f); }
    constexpr auto end() const noexcept { return make_int_itr(l); }
  };
  class revrep {
    const usize f, l;

  public:
    revrep(const usize f, const usize l) noexcept : f(l), l(f) {}
    auto begin() const noexcept {
      return std::make_reverse_iterator(make_int_itr(f));
    }
    auto end() const noexcept {
      return std::make_reverse_iterator(make_int_itr(l));
    }
  };
  template <class T> auto md_vec(const usize n, const T& value) {
    return std::vector<T>(n, value);
  }
  template <class... Args> auto md_vec(const usize n, Args... args) {
    return std::vector<decltype(md_vec(args...))>(n, md_vec(args...));
  }
  template <class T> constexpr T difference(const T& a, const T& b) {
    return a < b ? b - a : a - b;
  }
  template <class T> T scan() {
    T ret;
    std::cin >> ret;
    return ret;
  }

} // namespace n91
#include <cassert>
#include <cstdint>
#include <limits>
#include <vector>

namespace n91 {

  class eratosthenes {
    using field_type = std::uint_fast64_t;

  public:
    using container_type = std::vector<field_type>;
    using size_type = typename container_type::size_type;

  protected:
    static constexpr size_type WordSize =
      static_cast<size_type>(std::numeric_limits<field_type>::digits);

    container_type c;

  public:
    eratosthenes() noexcept : c() {}
    explicit eratosthenes(const size_type max)
      : c(max / WordSize + static_cast<size_type>(1),
        ~static_cast<field_type>(0)) {
      const size_type limit = c.size() * WordSize;
      c[static_cast<size_type>(0)] &= ~static_cast<field_type>(3);
      for (size_type i = static_cast<size_type>(2); i * i < limit; ++i) {
        if ((c[i / WordSize] & static_cast<field_type>(1) << i % WordSize) !=
          static_cast<field_type>(0)) {
          for (size_type j = i * i; j < limit; j += i) {
            c[j / WordSize] &= ~(static_cast<field_type>(1) << j % WordSize);
          }
        }
      }
    }

    bool test(const size_type i) const noexcept {
      assert(i < c.size() * WordSize);
      return (c[i / WordSize] & static_cast<field_type>(1) << i % WordSize) !=
        static_cast<field_type>(0);
    }
    bool operator[](const size_type i) const noexcept {
      assert(i < c.size() * WordSize);
      return (c[i / WordSize] & static_cast<field_type>(1) << i % WordSize) !=
        static_cast<field_type>(0);
    }
  };

} // namespace n91
#include <utility>
#include <vector>

namespace n91 {

  template <class T, class F>
  std::vector<T> filter(const std::vector<T>& a, const F& f) {
    std::vector<T> ret;
    ret.reserve(a.size());
    for (const T& e : a) {
      if (f(e)) {
        ret.push_back(e);
      }
    }
    ret.shrink_to_fit();
    return std::move(ret);
  }

} // namespace n91

#include <algorithm>
#include <iostream>
#include <set>
#include <utility>

namespace n91 {

  void main_() {
    const usize k = scan<usize>();
    const usize n = scan<usize>();
    const eratosthenes sieve(n);
    const auto ps =
      filter(std::vector<usize>(make_int_itr(k), make_int_itr(n + 1_z)),
        [&](const usize x) { return sieve[x]; });
    std::set<usize> hs;
    usize r = 0_z;
    usize max = 0_z;
    usize mem;
    for (const auto i : rep(0_z, ps.size())) {
      while (r != ps.size() && !hs.count(ps[r] % 9_z)) {
        hs.insert(ps[r] % 9_z);
        ++r;
      }
      if (max <= r - i) {
        max = r - i;
        mem = i;
      }
      hs.erase(ps[i] % 9_z);
    }
    std::cout << ps[mem] << std::endl;
  }

} // namespace n91

int main() {
  n91::main_();
  return 0;
}