#include <bits/stdc++.h>
#pragma GCC diagnostic ignored "-Wsign-compare"
#pragma GCC diagnostic ignored "-Wsign-conversion"
#define NDEBUG
#define SHOW(...) static_cast<void>(0)
//!===========================================================!//
//!  dP     dP                          dP                    !//
//!  88     88                          88                    !//
//!  88aaaaa88a .d8888b. .d8888b. .d888b88 .d8888b. 88d888b.  !//
//!  88     88  88ooood8 88'  '88 88'  '88 88ooood8 88'  '88  !//
//!  88     88  88.  ... 88.  .88 88.  .88 88.  ... 88        !//
//!  dP     dP  '88888P' '88888P8 '88888P8 '88888P' dP        !//
//!===========================================================!//
using ld = long double;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
constexpr unsigned int MOD = 1000000007;
template <typename T>
constexpr T INF = std::numeric_limits<T>::max() / 4;
template <typename F>
constexpr F PI = static_cast<F>(3.1415926535897932385);
std::mt19937 mt{std::random_device{}()};
template <typename T>
bool chmin(T& a, const T& b) { return a = std::min(a, b), a == b; }
template <typename T>
bool chmax(T& a, const T& b) { return a = std::max(a, b), a == b; }
template <typename T>
std::vector<T> Vec(const std::size_t n, T v) { return std::vector<T>(n, v); }
template <class... Args>
auto Vec(const std::size_t n, Args... args) { return std::vector<decltype(Vec(args...))>(n, Vec(args...)); }
template <typename T>
constexpr T popCount(const T u)
{
#ifdef __has_builtin
    return u == 0 ? T(0) : (T)__builtin_popcountll(u);
#else
    unsigned long long v = static_cast<unsigned long long>(u);
    return v = (v & 0x5555555555555555ULL) + (v >> 1 & 0x5555555555555555ULL), v = (v & 0x3333333333333333ULL) + (v >> 2 & 0x3333333333333333ULL), v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL, static_cast<T>(v * 0x0101010101010101ULL >> 56 & 0x7f);
#endif
}
template <typename T>
constexpr T log2p1(const T u)
{
#ifdef __has_builtin
    return u == 0 ? T(0) : T(64 - __builtin_clzll(u));
#else
    unsigned long long v = static_cast<unsigned long long>(u);
    return v = static_cast<unsigned long long>(v), v |= (v >> 1), v |= (v >> 2), v |= (v >> 4), v |= (v >> 8), v |= (v >> 16), v |= (v >> 32), popCount(v);
#endif
}
template <typename T>
constexpr T clog(const T v) { return v == 0 ? T(0) : log2p1(v - 1); }
template <typename T>
constexpr T msbp1(const T v) { return log2p1(v); }
template <typename T>
constexpr T lsbp1(const T v)
{
#ifdef __has_builtin
    return __builtin_ffsll(v);
#else
    return v == 0 ? T(0) : popCount((v & (-v)) - T(1)) + T(1);
#endif
}
template <typename T>
constexpr bool ispow2(const T v) { return popCount(v) == 1; }
template <typename T>
constexpr T ceil2(const T v) { return v == 0 ? T(1) : T(1) << log2p1(v - 1); }
template <typename T>
constexpr T floor2(const T v) { return v == 0 ? T(0) : T(1) << (log2p1(v) - 1); }
//!====================================================================================================!//
//!   888888ba           oo                         88888888b                   dP                     !//
//!   88    '8b                                     88                          88                     !//
//!  a88aaaa8P' 88d888b. dP 88d8b.d8b. .d8888b.    a88aaaa  d8888b. .d8888b. d8888P .d8888b. 88d888b.  !//
//!   88        88'  '88 88 88''88''88 88ooood8     88     88'  '88 88'  '""   88   88'  '88 88'  '88  !//
//!   88        88       88 88  88  88 88.  ...     88     88.  .88 88.  ...   88   88.  .88 88        !//
//!   dP        dP       dP dP  dP  dP '88888P'     dP     '88888P8 '88888P'   dP   '88888P' dP        !//
//!====================================================================================================!//
template <typename T>
std::vector<std::pair<T, std::size_t>> PrimeFactors(T n)
{
    std::vector<std::pair<T, std::size_t>> ans;
    for (T i = 2; i * i <= n; i++) {
        std::size_t cnt = 0;
        for (; n % i == 0; n /= i, cnt++) {}
        if (cnt > 0) { ans.push_back({i, cnt}); }
    }
    if (n > 1) { ans.push_back({n, 1}); }
    return ans;
}
//!================================================================!//
//!  888888ba  oo          oo                                      !//
//!  88    '8b                                                     !//
//!  88     88 dP dP   .dP dP .d8888b. .d8888b. 88d888b. .d8888b.  !//
//!  88     88 88 88   d8' 88 Y8ooooo. 88'  '88 88'  '88 Y8ooooo.  !//
//!  88    .8P 88 88 .88'  88       88 88.  .88 88             88  !//
//!  8888888P  dP 8888P'   dP '88888P' '88888P' dP       '88888P'  !//
//!================================================================!//
template <typename T>
std::vector<T> Divisors(const T n)
{
    std::vector<T> head, tail;
    for (T i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            head.push_back(i);
            if (i * i != n) { tail.push_back(n / i); }
        }
    }
    for (auto it = tail.rbegin(); it != tail.rend(); it++) { head.push_back(*it); }
    return head;
}
//!====================================================================================!//
//!    .88888.   a88888b. 888888ba        d88b       dP         a88888b. 8888ba.88ba   !//
//!   d8'   '88 d8'   '88 88    '8b       8''8       88        d8'   '88 88  '8b  '8b  !//
//!   88        88        88     88       d8b        88        88        88   88   88  !//
//!   88   YP88 88        88     88     d8P'8b       88        88        88   88   88  !//
//!   Y8.   .88 Y8.   .88 88    .8P     d8' '8bP     88        Y8.   .88 88   88   88  !//
//!    '88888'   Y88888P' 8888888P      '888P''YP    88888888P  Y88888P' dP   dP   dP  !//
//!====================================================================================!//
template <typename T>
constexpr T gcd(const T a, const T b) { return (b != 0) ? gcd(b, a % b) : a; }
template <typename T>
constexpr T lcm(const T a, const T b) { return (a == 0 and b == 0) ? (T)0 : (a / gcd(a, b)) * b; }
//!============================================!//
//!    8888ba.88ba             oo              !//
//!    88  '8b  '8b                            !//
//!    88   88   88  .d8888b.  dP  88d888b.    !//
//!    88   88   88  88'  '88  88  88'  '88    !//
//!    88   88   88  88.  .88  88  88    88    !//
//!    dP   dP   dP  '88888P8  dP  dP    dP    !//
//!============================================!//
int main()
{
    int N, K;
    std::cin >> N >> K;
    int max = 1, ans = 0;
    for (int v = 1; v < N; v++) {
        const auto fac = PrimeFactors(gcd(v, N));
        int i = 0;
        for (const auto& p : fac) { i += p.second; }
        if (i >= K) {
            const int d = Divisors(v).size();
            if (max < d) { max = d, ans = v; }
        }
    }
    std::cout << ans << std::endl;
    return 0;
}