Mr. Chanek lives in a city represented as a plane. He wants to build an amusement park in the shape of a circle of radius r. The circle must touch the origin (point (0, 0)).

There are n bird habitats that can be a photo spot for the tourists in the park. The i-th bird habitat is at point p_i = (x_i, y_i). 

Find the minimum radius r of a park with at least k bird habitats inside. 

A point is considered to be inside the park if and only if the distance between p_i and the center of the park is less than or equal to the radius of the park. Note that the center and the radius of the park do not need to be integers.

In this problem, it is guaranteed that the given input always has a solution with r ≤ 2 ⋅ 10^5.

Input

The first line contains two integers n and k (1 ≤ n ≤ 10^5, 1 ≤ k ≤ n) — the number of bird habitats in the city and the number of bird habitats required to be inside the park.

The i-th of the next n lines contains two integers x_i and y_i (0 ≤ |x_i|, |y_i| ≤ 10^5) — the position of the i-th bird habitat.

Output

Output a single real number r denoting the minimum radius of a park with at least k bird habitats inside. It is guaranteed that the given input always has a solution with r ≤ 2 ⋅ 10^5.

Your answer is considered correct if its absolute or relative error does not exceed 10^{-4}.

Formally, let your answer be a, and the jury's answer be b. Your answer is accepted if and only if \frac{|a - b|}{max{(1, |b|)}} ≤ 10^{-4}.

Examples

Input


8 4
-3 1
-4 4
1 5
2 2
2 -2
-2 -4
-1 -1
-6 0


Output


3.1622776589


Input


1 1
0 0


Output


0.0000000000

Note

In the first example, Mr. Chanek can put the center of the park at (-3, -1) with radius √{10} ≈ 3.162. It can be proven this is the minimum r.

The following illustrates the first example. The blue points represent bird habitats and the red circle represents the amusement park.

<image>
#pragma region Macros
#pragma comment(linker, "/stack:200000000")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,fma,abm,mmx,avx,avx2,tune=native")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,fma,abm,mmx,avx,avx2")
// #pragma GCC target("avx2")
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#define ll long long
using ld = long double;
#define rep2(i, a, b) for(ll i = (a); i <= (b); i++)
#define rep3(i, a, b) for(ll i = (a); i >= (b); --i)
#define rep(i, n) for(ll i = 0; i < n; ++i)
#define each(i, a) for(auto &&i : a)
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define vll vector<ll>
#define vpi vector<pii>
#define vpll vector<pll>
#define overload2(_1, _2, name, ...) name
#define vec(type, name, ...) vector<type> name(__VA_ARGS__)
#define VEC(type, name, size)                                                                                                                                  \
    vector<type> name(size);                                                                                                                                   \
    IN(name)
#define VEC2(type, name1, name2, size)                                                                                                                         \
    vector<type> name1(size), name2(size);                                                                                                                     \
    for(int i = 0; i < size; i++) IN(name1[i], name2[i])
#define VEC3(type, name1, name2, name3, size)                                                                                                                  \
    vector<type> name1(size), name2(size), name3(size);                                                                                                        \
    for(int i = 0; i < size; i++) IN(name1[i], name2[i], name3[i])
#define vv(type, name, h, ...) vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define VV(type, name, h, w)                                                                                                                                   \
    vector<vector<type>> name(h, vector<type>(w));                                                                                                             \
    IN(name)
#define vvv(type, name, h, w, ...) vector<vector<vector<type>>> name(h, vector<vector<type>>(w, vector<type>(__VA_ARGS__)))
#define vvvv(type, name, a, b, c, ...)                                                                                                                         \
    vector<vector<vector<vector<type>>>> name(a, vector<vector<vector<type>>>(b, vector<vector<type>>(c, vector<type>(__VA_ARGS__))))
#define mt make_tuple
#define fi first
#define se second
#define all(c) begin(c), end(c)
#define rall(c) rbegin(c), rend(c)
#define SORT(v) sort(all(v))
#define REV(v) reverse(all(v))
template <class T = ll, class S> T SUM(const S &v) { return accumulate(all(v), T(0)); }
#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))
#define lb(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define ub(c, x) distance((c).begin(), upper_bound(all(c), (x)))
using namespace std;
constexpr pii dx4[4] = {pii{1, 0}, pii{0, 1}, pii{-1, 0}, pii{0, -1}};
constexpr pii dx8[8] = {{1, 0}, {1, 1}, {0, 1}, {-1, 1}, {-1, 0}, {-1, -1}, {0, -1}, {1, -1}};
const string YESNO[2] = {"NO", "YES"};
const string YesNo[2] = {"No", "Yes"};
const string yesno[2] = {"no", "yes"};
void YES(bool t = 1) { cout << YESNO[t] << endl; }
void NO(bool t = 1) { YES(!t); }
void Yes(bool t = 1) { cout << YesNo[t] << endl; }
void No(bool t = 1) { Yes(!t); }
void yes(bool t = 1) { cout << yesno[t] << endl; }
void no(bool t = 1) { yes(!t); }
template <class T> using vc = vector<T>;
template <class T> using vvc = vector<vc<T>>;
template <class T> using vvvc = vector<vvc<T>>;
template <class T> using vvvvc = vector<vvvc<T>>;
template <class T> using pq = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;
#define si(c) (int)(c).size()
#define INT(...)                                                                                                                                               \
    int __VA_ARGS__;                                                                                                                                           \
    IN(__VA_ARGS__)
#define LL(...)                                                                                                                                                \
    ll __VA_ARGS__;                                                                                                                                            \
    IN(__VA_ARGS__)
#define STR(...)                                                                                                                                               \
    string __VA_ARGS__;                                                                                                                                        \
    IN(__VA_ARGS__)
#define CHR(...)                                                                                                                                               \
    char __VA_ARGS__;                                                                                                                                          \
    IN(__VA_ARGS__)
#define DBL(...)                                                                                                                                               \
    double __VA_ARGS__;                                                                                                                                        \
    IN(__VA_ARGS__)
int scan() { return getchar(); }
void scan(int &a) { cin >> a; }
void scan(long long &a) { cin >> a; }
void scan(char &a) { cin >> a; }
void scan(double &a) { cin >> a; }
void scan(string &a) { cin >> a; }
template <class T, class S> void scan(pair<T, S> &p) { scan(p.first), scan(p.second); }
template <class T> void scan(vector<T> &);
template <class T> void scan(vector<T> &a) {
    for(auto &i : a) scan(i);
}
template <class T> void scan(T &a) { cin >> a; }
void IN() {}
template <class Head, class... Tail> void IN(Head &head, Tail &...tail) {
    scan(head);
    IN(tail...);
}

template <class T, class S> inline bool chmax(T &a, const S &b) { return (a < b ? a = b, 1 : 0); }
template <class T, class S> inline bool chmin(T &a, const S &b) { return (a > b ? a = b, 1 : 0); }
vi iota(int n) {
    vi a(n);
    iota(all(a), 0);
    return a;
}
template <typename T> vi iota(vector<T> &a, bool greater = false) {
    vi res(a.size());
    iota(all(res), 0);
    sort(all(res), [&](int i, int j) {
        if(greater) return a[i] > a[j];
        return a[i] < a[j];
    });
    return res;
}
#define UNIQUE(x) sort(all(x)), x.erase(unique(all(x)), x.end())

template <class T> T ceil(T x, T y) {
    assert(y >= 1);
    return (x > 0 ? (x + y - 1) / y : x / y);
}

template <class T> T floor(T x, T y) {
    assert(y >= 1);
    return (x > 0 ? x / y : (x + y - 1) / y);
}
template <class T> T POW(T x, int n) {
    T res = 1;
    for(; n; n >>= 1, x *= x)
        if(n & 1) res *= x;
    return res;
}
template <class T, class S> T POW(T x, S n, const ll &mod) {
    T res = 1;
    for(; n; n >>= 1, x = x * x % mod)
        if(n & 1) res = res * x % mod;
    return res;
}
vector<pll> factor(ll x) {
    vector<pll> ans;
    for(ll i = 2; i * i <= x; i++)
        if(x % i == 0) {
            ans.push_back({i, 1});
            while((x /= i) % i == 0) ans.back().second++;
        }
    if(x != 1) ans.push_back({x, 1});
    return ans;
}
template <class T> vector<T> divisor(T x) {
    vector<T> ans;
    for(T i = 1; i * i <= x; i++)
        if(x % i == 0) {
            ans.pb(i);
            if(i * i != x) ans.pb(x / i);
        }
    return ans;
}
template <typename T> void zip(vector<T> &x) {
    vector<T> y = x;
    UNIQUE(y);
    for(int i = 0; i < x.size(); ++i) { x[i] = lb(y, x[i]); }
}
template <class S> void fold_in(vector<S> &v) {}
template <typename Head, typename... Tail, class S> void fold_in(vector<S> &v, Head &&a, Tail &&...tail) {
    for(auto e : a) v.emplace_back(e);
    fold_in(v, tail...);
}
template <class S> void renumber(vector<S> &v) {}
template <typename Head, typename... Tail, class S> void renumber(vector<S> &v, Head &&a, Tail &&...tail) {
    for(auto &&e : a) e = lb(v, e);
    renumber(v, tail...);
}
template <class S, class... Args> vector<S> zip(vector<S> &head, Args &&...args) {
    vector<S> v;
    fold_in(v, head, args...);
    sort(all(v)), v.erase(unique(all(v)), v.end());
    renumber(v, head, args...);
    return v;
}

// x in [l, r)
template <class T, class S> bool inc(const T &x, const S &l, const S &r) { return l <= x and x < r; }
// (a, b) in [lx, rx) * [ly, ry)
template <class T, class S> bool inc(const pair<T, T> &x, const S &lx, const S &ly, const S &rx, const S &ry) { return inc(x.fi, lx, rx) && inc(x.se, ly, ry); }

constexpr ll ten(int n) { return n == 0 ? 1 : ten(n - 1) * 10; }
// bit 演算系
ll pow2(int i) { return 1LL << i; }
int topbit(signed t) { return t == 0 ? -1 : 31 - __builtin_clz(t); }
int topbit(ll t) { return t == 0 ? -1 : 63 - __builtin_clzll(t); }
int lowbit(signed a) { return a == 0 ? 32 : __builtin_ctz(a); }
int lowbit(ll a) { return a == 0 ? 64 : __builtin_ctzll(a); }
// int allbit(int n) { return (1 << n) - 1; }
ll allbit(ll n) { return (1LL << n) - 1; }
int popcount(signed t) { return __builtin_popcount(t); }
int popcount(ll t) { return __builtin_popcountll(t); }
bool ispow2(int i) { return i && (i & -i) == i; }

ll rnd(ll l, ll r) { //[l, r)
#ifdef _LOCAL
    static mt19937_64 gen;
#else
    static mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());
#endif
    return uniform_int_distribution<ll>(l, r - 1)(gen);
}
ll rnd(ll n) { return rnd(0, n); }

template <class t> void random_shuffle(vc<t> &a) { rep(i, si(a)) swap(a[i], a[rnd(0, i + 1)]); }

int in() {
    int x;
    cin >> x;
    return x;
}
ll lin() {
    unsigned long long x;
    cin >> x;
    return x;
}

template <class T, class S> pair<T, S> operator-(const pair<T, S> &x, const pair<T, S> &y) { return pair<T, S>(x.fi - y.fi, x.se - y.se); }
template <class T, class S> pair<T, S> operator+(const pair<T, S> &x, const pair<T, S> &y) { return pair<T, S>(x.fi + y.fi, x.se + y.se); }
template <class T> pair<T, T> operator&(const pair<T, T> &l, const pair<T, T> &r) { return pair<T, T>(max(l.fi, r.fi), min(l.se, r.se)); }
template <class T, class S> pair<T, S> operator+=(pair<T, S> &l, const pair<T, S> &r) { return l = l + r; }
template <class T, class S> pair<T, S> operator-=(pair<T, S> &l, const pair<T, S> &r) { return l = l - r; }
template <class T> bool intersect(const pair<T, T> &l, const pair<T, T> &r) { return (l.se < r.se ? r.fi < l.se : l.fi < r.se); }

template <class T> ll operator*(const pair<T, T> &x, const pair<T, T> &y) { return (ll)x.fi * y.fi + (ll)x.se * y.se; }

template <typename T> struct edge {
    int from, to;
    T cost;
    int id;
    edge(int to, T cost) : from(-1), to(to), cost(cost) {}
    edge(int from, int to, T cost) : from(from), to(to), cost(cost) {}
    edge(int from, int to, T cost, int id) : from(from), to(to), cost(cost), id(id) {}
    constexpr bool operator<(const edge<T> &rhs) const noexcept { return cost < rhs.cost; }
    edge &operator=(const int &x) {
        to = x;
        return *this;
    }
    operator int() const { return to; }
};
template <typename T> using Edges = vector<edge<T>>;

using Tree = vector<vector<int>>;
using Graph = vector<vector<int>>;
template <class T> using Wgraph = vector<vector<edge<T>>>;
Graph getG(int n, int m = -1, bool directed = false, int margin = 1) {
    Tree res(n);
    if(m == -1) m = n - 1;
    while(m--) {
        int a, b;
        cin >> a >> b;
        a -= margin, b -= margin;
        res[a].emplace_back(b);
        if(!directed) res[b].emplace_back(a);
    }
    return res;
}
Graph getTreeFromPar(int n, int margin = 1) {
    Graph res(n);
    for(int i = 1; i < n; i++) {
        int a;
        cin >> a;
        res[a - margin].emplace_back(i);
    }
    return res;
}
template <class T> Wgraph<T> getWg(int n, int m = -1, bool directed = false, int margin = 1) {
    Wgraph<T> res(n);
    if(m == -1) m = n - 1;
    while(m--) {
        int a, b;
        T c;
        cin >> a >> b >> c;
        a -= margin, b -= margin;
        res[a].emplace_back(b, c);
        if(!directed) res[b].emplace_back(a, c);
    }
    return res;
}
void add(Graph &G, int x, int y) { G[x].eb(y), G[y].eb(x); }
template <class S, class T> void add(Wgraph<S> &G, int x, int y, T c) { G[x].eb(y, c), G[y].eb(x, c); }

#define i128 __int128_t
#define ull unsigned long long int
#define TEST                                                                                                                                                   \
    INT(testcases);                                                                                                                                            \
    while(testcases--)
template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
    for(auto it = begin(v); it != end(v); ++it) {
        if(it == begin(v))
            os << *it;
        else
            os << " " << *it;
    }
    return os;
}
template <class T, class S> ostream &operator<<(ostream &os, const pair<T, S> &p) {
    os << p.first << " " << p.second;
    return os;
}
template <class S, class T> string to_string(pair<S, T> p) { return "(" + to_string(p.first) + "," + to_string(p.second) + ")"; }
string to_string(string s) { return "\"" + s + "\""; }
string to_string(char c) { return string(1, c); }
template <class T> string to_string(vector<T> s) {
    string res = "{";
    for(auto it = s.begin(); it != s.end(); it++) res += to_string(*it) + (next(it) == s.end() ? "" : ", ");
    return res + "}";
}
template <class T> string to_string(set<T> s) {
    string res = "{";
    for(auto it = s.begin(); it != s.end(); it++) res += to_string(*it), res += (next(it) == end(s) ? "" : ", ");
    return res + "}";
}

#define endl '\n'

#ifdef _LOCAL
void dump() { cerr << endl; }
template <class Head, class... Tail> void dump(Head head, Tail... tail) {
    cerr << to_string(head) << " ";
    dump(tail...);
}
#undef endl
#define debug(x)                                                                                                                                               \
    cout << #x << ": ";                                                                                                                                        \
    dump(x)
#else
void dump() {}
template <class Head, class... Tail> void dump(Head head, Tail... tail) {}
#define debug(x)
#endif
template <class T> void print(const T &a) { cout << a; }
void OUT() { cout << endl; }
template <class Head, class... Tail> void OUT(const Head &head, const Tail &...tail) {
    print(head);
    if(sizeof...(tail)) cout << ' ';
    OUT(tail...);
}

template <typename T> static constexpr T inf = numeric_limits<T>::max() / 2;
struct Setup_io {
    Setup_io() {
        ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
        cout << fixed << setprecision(15);
    }
} setup_io;
#define drop(s) cout << #s << endl, exit(0)

template <int N> struct ndFORarray {
    std::array<int, N> v;
    ndFORarray(std::array<int, N> v_) : v(v_) {}
    struct ndFORitr {
        const std::array<int, N> &v;
        std::array<int, N> tmp;
        bool is_end;
        ndFORitr(const std::array<int, N> &v_) : v(v_), tmp(), is_end(false) {}
        bool operator!=(const ndFORitr &) const { return !is_end; }
        void operator++() {
            int pos = N - 1;
            while(pos != -1) {
                tmp[pos] += 1;
                if(tmp[pos] == v[pos]) {
                    tmp[pos] = 0;
                    pos -= 1;
                } else {
                    break;
                }
            }
            if(pos == -1) { is_end = true; }
        }
        const std::array<int, N> &operator*() const { return tmp; }
    };
    ndFORitr begin() const { return ndFORitr(v); }
    ndFORitr end() const { return ndFORitr(v); }
};

struct ndFORvector {
    std::vector<int> v;
    ndFORvector(std::vector<int> v_) : v(v_) {}
    struct ndFORitr {
        const std::vector<int> &v;
        std::vector<int> tmp;
        bool is_end;
        ndFORitr(const std::vector<int> &v_) : v(v_), tmp(v.size(), 0), is_end(false) {}
        bool operator!=(const ndFORitr &) const { return !is_end; }
        void operator++() {
            int pos = v.size() - 1;
            while(pos != -1) {
                tmp[pos] += 1;
                if(tmp[pos] == v[pos]) {
                    tmp[pos] = 0;
                    pos -= 1;
                } else {
                    break;
                }
            }
            if(pos == -1) { is_end = true; }
        }
        const std::vector<int> &operator*() const { return tmp; }
    };
    ndFORitr begin() const { return ndFORitr(v); }
    ndFORitr end() const { return ndFORitr(v); }
};

auto ndFOR(std::vector<int> v) { return ndFORvector(v); }
template <class... Ts> auto ndFOR(Ts... v) { return ndFORarray<std::tuple_size<std::tuple<Ts...>>::value>({v...}); }
template <class F> struct REC {
    F f;
    REC(F &&f_) : f(std::forward<F>(f_)) {}
    template <class... Args> auto operator()(Args &&...args) const { return f(*this, std::forward<Args>(args)...); }
};

template <class S> vector<pair<S, int>> runLength(const vector<S> &v) {
    vector<pair<S, int>> res;
    for(auto &e : v) {
        if(res.empty() or res.back().fi != e)
            res.eb(e, 1);
        else
            res.back().se++;
    }
    return res;
}
vector<pair<char, int>> runLength(const string &v) {
    vector<pair<char, int>> res;
    for(auto &e : v) {
        if(res.empty() or res.back().fi != e)
            res.eb(e, 1);
        else
            res.back().se++;
    }
    return res;
}

template <class T = int> struct Imos {
    int n;
    vector<T> a;
    Imos(int _n) : n(_n), a(_n + 1) {}
    void add(int l, int r, T val = 1) {
        if(l >= r) return;
        l = clamp(l, 0, n);
        r = clamp(r, 0, n + 1);
        a[l] += val;
        if(r <= n) a[r] -= val;
    }
    void build() {
        for(int i = 0; i < n; i++) a[i + 1] += a[i];
    }
    const T &operator[](int k) { return a[k]; }
};

template <class T> struct RUI {
    vector<T> a;
    RUI(const vector<T> &v) : a(v.size() + 1) {
        for(int i = 0; i < v.size(); i++) a[i + 1] = a[i] + v[i];
    }
    T get(int l, int r) { return a[r] - a[l]; }
};

template <class T, class F> T bin_search(T ok, T ng, const F &f) {
    while(abs(ok - ng) > 1) {
        T mid = ok + ng >> 1;
        (f(mid) ? ok : ng) = mid;
    }
    return ok;
}
#pragma endregion

namespace std {
bool operator<(const complex<double> &a, const complex<double> &b) { return a.real() != b.real() ? a.real() < b.real() : a.imag() < b.imag(); }
} // namespace std

namespace Geometry {
using Real = double;
using Point = complex<Real>;
const Real EPS = 1e-8, PI = acos(-1);

inline bool eq(Real a, Real b) { return fabs(b - a) < EPS; }

Point operator*(const Point &p, const Real &d) { return Point(real(p) * d, imag(p) * d); }

istream &operator>>(istream &is, Point &p) {
    Real a, b;
    is >> a >> b;
    p = Point(a, b);
    return is;
}

ostream &operator<<(ostream &os, Point &p) { return os << fixed << setprecision(10) << p.real() << " " << p.imag(); }

// 点 p を反時計回りに theta 回転
Point rotate(Real theta, const Point &p) { return Point(cos(theta) * p.real() - sin(theta) * p.imag(), sin(theta) * p.real() + cos(theta) * p.imag()); }

Real radian_to_degree(Real r) { return (r * 180.0 / PI); }

Real degree_to_radian(Real d) { return (d * PI / 180.0); }

// a-b-c の角度のうち小さい方を返す
Real get_angle(const Point &a, const Point &b, const Point &c) {
    const Point v(b - a), w(c - b);
    Real alpha = atan2(v.imag(), v.real()), beta = atan2(w.imag(), w.real());
    if(alpha > beta) swap(alpha, beta);
    Real theta = (beta - alpha);
    return min(theta, 2 * acos(-1) - theta);
}

struct Line {
    Point a, b;

    Line() = default;

    Line(Point a, Point b) : a(a), b(b) {}

    Line(Real A, Real B, Real C) // Ax + By = C
    {
        if(eq(A, 0))
            a = Point(0, C / B), b = Point(1, C / B);
        else if(eq(B, 0))
            b = Point(C / A, 0), b = Point(C / A, 1);
        else
            a = Point(0, C / B), b = Point(C / A, 0);
    }

    friend ostream &operator<<(ostream &os, Line &p) { return os << p.a << " to " << p.b; }

    friend istream &operator>>(istream &is, Line &a) { return is >> a.a >> a.b; }
};

struct Segment : Line {
    Segment() = default;

    Segment(Point a, Point b) : Line(a, b) {}
};

struct Circle {
    Point p;
    Real r;

    Circle() = default;

    Circle(Point p, Real r) : p(p), r(r) {}
};

using Points = vector<Point>;
using Polygon = vector<Point>;
using Segments = vector<Segment>;
using Lines = vector<Line>;
using Circles = vector<Circle>;

Real cross(const Point &a, const Point &b) { return real(a) * imag(b) - imag(a) * real(b); }

Real dot(const Point &a, const Point &b) { return real(a) * real(b) + imag(a) * imag(b); }

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_C
// 点の回転方向
int ccw(const Point &a, Point b, Point c) {
    b = b - a, c = c - a;
    if(cross(b, c) > EPS) return +1;  // "COUNTER_CLOCKWISE"
    if(cross(b, c) < -EPS) return -1; // "CLOCKWISE"
    if(dot(b, c) < 0) return +2;      // "ONLINE_BACK"
    if(norm(b) < norm(c)) return -2;  // "ONLINE_FRONT"
    return 0;                         // "ON_SEGMENT"
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_A
// 平行判定
bool parallel(const Line &a, const Line &b) { return eq(cross(a.b - a.a, b.b - b.a), 0.0); }

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_A
// 垂直判定
bool orthogonal(const Line &a, const Line &b) { return eq(dot(a.a - a.b, b.a - b.b), 0.0); }

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_A
// 射影
// 直線 l に p から垂線を引いた交点を求める
Point projection(const Line &l, const Point &p) {
    double t = dot(p - l.a, l.a - l.b) / norm(l.a - l.b);
    return l.a + (l.a - l.b) * t;
}

Point projection(const Segment &l, const Point &p) {
    double t = dot(p - l.a, l.a - l.b) / norm(l.a - l.b);
    return l.a + (l.a - l.b) * t;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_B
// 反射
// 直線 l を対称軸として点 p  と線対称にある点を求める
Point reflection(const Line &l, const Point &p) { return p + (projection(l, p) - p) * 2.0; }

bool intersect(const Line &l, const Point &p) { return abs(ccw(l.a, l.b, p)) != 1; }

bool intersect(const Line &l, const Line &m) { return abs(cross(l.b - l.a, m.b - m.a)) > EPS || abs(cross(l.b - l.a, m.b - l.a)) < EPS; }

bool intersect(const Segment &s, const Point &p) { return ccw(s.a, s.b, p) == 0; }

bool intersect(const Line &l, const Segment &s) { return cross(l.b - l.a, s.a - l.a) * cross(l.b - l.a, s.b - l.a) < EPS; }

Real distance(const Line &l, const Point &p);

bool intersect(const Circle &c, const Line &l) { return distance(l, c.p) <= c.r + EPS; }

bool intersect(const Circle &c, const Point &p) { return abs(abs(p - c.p) - c.r) < EPS; }

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_B
bool intersect(const Segment &s, const Segment &t) { return ccw(s.a, s.b, t.a) * ccw(s.a, s.b, t.b) <= 0 && ccw(t.a, t.b, s.a) * ccw(t.a, t.b, s.b) <= 0; }

int intersect(const Circle &c, const Segment &l) {
    if(norm(projection(l, c.p) - c.p) - c.r * c.r > EPS) return 0;
    auto d1 = abs(c.p - l.a), d2 = abs(c.p - l.b);
    if(d1 < c.r + EPS && d2 < c.r + EPS) return 0;
    if(d1 < c.r - EPS && d2 > c.r + EPS || d1 > c.r + EPS && d2 < c.r - EPS) return 1;
    const Point h = projection(l, c.p);
    if(dot(l.a - h, l.b - h) < 0) return 2;
    return 0;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_A&lang=jp
int intersect(Circle c1, Circle c2) {
    if(c1.r < c2.r) swap(c1, c2);
    Real d = abs(c1.p - c2.p);
    if(c1.r + c2.r < d) return 4;
    if(eq(c1.r + c2.r, d)) return 3;
    if(c1.r - c2.r < d) return 2;
    if(eq(c1.r - c2.r, d)) return 1;
    return 0;
}

Real distance(const Point &a, const Point &b) { return abs(a - b); }

Real distance(const Line &l, const Point &p) { return abs(p - projection(l, p)); }

Real distance(const Line &l, const Line &m) { return intersect(l, m) ? 0 : distance(l, m.a); }

Real distance(const Segment &s, const Point &p) {
    Point r = projection(s, p);
    if(intersect(s, r)) return abs(r - p);
    return min(abs(s.a - p), abs(s.b - p));
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_D
Real distance(const Segment &a, const Segment &b) {
    if(intersect(a, b)) return 0;
    return min({distance(a, b.a), distance(a, b.b), distance(b, a.a), distance(b, a.b)});
}

Real distance(const Line &l, const Segment &s) {
    if(intersect(l, s)) return 0;
    return min(distance(l, s.a), distance(l, s.b));
}

Point crosspoint(const Line &l, const Line &m) {
    Real A = cross(l.b - l.a, m.b - m.a);
    Real B = cross(l.b - l.a, l.b - m.a);
    if(eq(abs(A), 0.0) && eq(abs(B), 0.0)) return m.a;
    return m.a + (m.b - m.a) * B / A;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_C
Point crosspoint(const Segment &l, const Segment &m) { return crosspoint(Line(l), Line(m)); }

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_D
pair<Point, Point> crosspoint(const Circle &c, const Line l) {
    Point pr = projection(l, c.p);
    Point e = (l.b - l.a) / abs(l.b - l.a);
    if(eq(distance(l, c.p), c.r)) return {pr, pr};
    double base = sqrt(c.r * c.r - norm(pr - c.p));
    return {pr - e * base, pr + e * base};
}

pair<Point, Point> crosspoint(const Circle &c, const Segment &l) {
    Line aa = Line(l.a, l.b);
    if(intersect(c, l) == 2) return crosspoint(c, aa);
    auto ret = crosspoint(c, aa);
    if(dot(l.a - ret.first, l.b - ret.first) < 0)
        ret.second = ret.first;
    else
        ret.first = ret.second;
    return ret;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_E
pair<Point, Point> crosspoint(const Circle &c1, const Circle &c2) {
    Real d = abs(c1.p - c2.p);
    Real a = acos((c1.r * c1.r + d * d - c2.r * c2.r) / (2 * c1.r * d));
    Real t = atan2(c2.p.imag() - c1.p.imag(), c2.p.real() - c1.p.real());
    Point p1 = c1.p + Point(cos(t + a) * c1.r, sin(t + a) * c1.r);
    Point p2 = c1.p + Point(cos(t - a) * c1.r, sin(t - a) * c1.r);
    return {p1, p2};
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_F
// 点 p を通る円 c の接線
pair<Point, Point> tangent(const Circle &c1, const Point &p2) { return crosspoint(c1, Circle(p2, sqrt(norm(c1.p - p2) - c1.r * c1.r))); }

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_G
// 円 c1, c2 の共通接線
Lines tangent(Circle c1, Circle c2) {
    Lines ret;
    if(c1.r < c2.r) swap(c1, c2);
    Real g = norm(c1.p - c2.p);
    if(eq(g, 0)) return ret;
    Point u = (c2.p - c1.p) / sqrt(g);
    Point v = rotate(PI * 0.5, u);
    for(int s : {-1, 1}) {
        Real h = (c1.r + s * c2.r) / sqrt(g);
        if(eq(1 - h * h, 0)) {
            ret.emplace_back(c1.p + u * c1.r, c1.p + (u + v) * c1.r);
        } else if(1 - h * h > 0) {
            Point uu = u * h, vv = v * sqrt(1 - h * h);
            ret.emplace_back(c1.p + (uu + vv) * c1.r, c2.p - (uu + vv) * c2.r * s);
            ret.emplace_back(c1.p + (uu - vv) * c1.r, c2.p - (uu - vv) * c2.r * s);
        }
    }
    return ret;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_3_B
// 凸性判定
bool is_convex(const Polygon &p) {
    int n = (int)p.size();
    for(int i = 0; i < n; i++) {
        if(ccw(p[(i + n - 1) % n], p[i], p[(i + 1) % n]) == -1) return false;
    }
    return true;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_A
// 凸包
Polygon convex_hull(Polygon &p) {
    int n = (int)p.size(), k = 0;
    if(n <= 2) return p;
    sort(p.begin(), p.end());
    vector<Point> ch(2 * n);
    for(int i = 0; i < n; ch[k++] = p[i++]) {
        while(k >= 2 && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < EPS) --k;
    }
    for(int i = n - 2, t = k + 1; i >= 0; ch[k++] = p[i--]) {
        while(k >= t && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < EPS) --k;
    }
    ch.resize(k - 1);
    return ch;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_3_C
// 多角形と点の包含判定
enum { OUTTT, ONNN, INNN };

int contains(const Polygon &Q, const Point &p) {
    bool in = false;
    for(int i = 0; i < Q.size(); i++) {
        Point a = Q[i] - p, b = Q[(i + 1) % Q.size()] - p;
        if(a.imag() > b.imag()) swap(a, b);
        if(a.imag() <= 0 && 0 < b.imag() && cross(a, b) < 0) in = !in;
        if(cross(a, b) == 0 && dot(a, b) <= 0) return ONNN;
    }
    return in ? INNN : OUTTT;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1033
// 線分の重複除去
void merge_segments(vector<Segment> &segs) {

    auto merge_if_able = [](Segment &s1, const Segment &s2) {
        if(abs(cross(s1.b - s1.a, s2.b - s2.a)) > EPS) return false;
        if(ccw(s1.a, s2.a, s1.b) == 1 || ccw(s1.a, s2.a, s1.b) == -1) return false;
        if(ccw(s1.a, s1.b, s2.a) == -2 || ccw(s2.a, s2.b, s1.a) == -2) return false;
        s1 = Segment(min(s1.a, s2.a), max(s1.b, s2.b));
        return true;
    };

    for(int i = 0; i < segs.size(); i++) {
        if(segs[i].b < segs[i].a) swap(segs[i].a, segs[i].b);
    }
    for(int i = 0; i < segs.size(); i++) {
        for(int j = i + 1; j < segs.size(); j++) {
            if(merge_if_able(segs[i], segs[j])) { segs[j--] = segs.back(), segs.pop_back(); }
        }
    }
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1033
// 線分アレンジメント
// 任意の2線分の交点を頂点としたグラフを構築する
vector<vector<int>> segment_arrangement(vector<Segment> &segs, vector<Point> &ps) {
    vector<vector<int>> g;
    int N = (int)segs.size();
    for(int i = 0; i < N; i++) {
        ps.emplace_back(segs[i].a);
        ps.emplace_back(segs[i].b);
        for(int j = i + 1; j < N; j++) {
            const Point p1 = segs[i].b - segs[i].a;
            const Point p2 = segs[j].b - segs[j].a;
            if(cross(p1, p2) == 0) continue;
            if(intersect(segs[i], segs[j])) { ps.emplace_back(crosspoint(segs[i], segs[j])); }
        }
    }
    sort(begin(ps), end(ps));
    ps.erase(unique(begin(ps), end(ps)), end(ps));

    int M = (int)ps.size();
    g.resize(M);
    for(int i = 0; i < N; i++) {
        vector<int> vec;
        for(int j = 0; j < M; j++) {
            if(intersect(segs[i], ps[j])) { vec.emplace_back(j); }
        }
        for(int j = 1; j < vec.size(); j++) {
            g[vec[j - 1]].push_back(vec[j]);
            g[vec[j]].push_back(vec[j - 1]);
        }
    }
    return (g);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_C
// 凸多角形の切断
// 直線 l.a-l.b で切断しその左側にできる凸多角形を返す
Polygon convex_cut(const Polygon &U, Line l) {
    Polygon ret;
    for(int i = 0; i < U.size(); i++) {
        Point now = U[i], nxt = U[(i + 1) % U.size()];
        if(ccw(l.a, l.b, now) != -1) ret.push_back(now);
        if(ccw(l.a, l.b, now) * ccw(l.a, l.b, nxt) < 0) { ret.push_back(crosspoint(Line(now, nxt), l)); }
    }
    return (ret);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_3_A
// 多角形の面積
Real area(const Polygon &p) {
    Real A = 0;
    for(int i = 0; i < p.size(); ++i) { A += cross(p[i], p[(i + 1) % p.size()]); }
    return A * 0.5;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_7_H
// 円と多角形の共通部分の面積
Real area(const Polygon &p, const Circle &c) {
    if(p.size() < 3) return 0.0;
    function<Real(Circle, Point, Point)> cross_area = [&](const Circle &c, const Point &a, const Point &b) {
        Point va = c.p - a, vb = c.p - b;
        Real f = cross(va, vb), ret = 0.0;
        if(eq(f, 0.0)) return ret;
        if(max(abs(va), abs(vb)) < c.r + EPS) return f;
        if(distance(Segment(a, b), c.p) > c.r - EPS) return c.r * c.r * arg(vb * conj(va));
        auto u = crosspoint(c, Segment(a, b));
        vector<Point> tot{a, u.first, u.second, b};
        for(int i = 0; i + 1 < tot.size(); i++) { ret += cross_area(c, tot[i], tot[i + 1]); }
        return ret;
    };
    Real A = 0;
    for(int i = 0; i < p.size(); i++) { A += cross_area(c, p[i], p[(i + 1) % p.size()]); }
    return A;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_B
// 凸多角形の直径(最遠頂点対間距離)
Real convex_diameter(const Polygon &p) {
    int N = (int)p.size();
    int is = 0, js = 0;
    for(int i = 1; i < N; i++) {
        if(p[i].imag() > p[is].imag()) is = i;
        if(p[i].imag() < p[js].imag()) js = i;
    }
    Real maxdis = norm(p[is] - p[js]);

    int maxi, maxj, i, j;
    i = maxi = is;
    j = maxj = js;
    do {
        if(cross(p[(i + 1) % N] - p[i], p[(j + 1) % N] - p[j]) >= 0) {
            j = (j + 1) % N;
        } else {
            i = (i + 1) % N;
        }
        if(norm(p[i] - p[j]) > maxdis) {
            maxdis = norm(p[i] - p[j]);
            maxi = i;
            maxj = j;
        }
    } while(i != is || j != js);
    return sqrt(maxdis);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_5_A
// 最近点対
Real closest_pair(Points ps) {
    if(ps.size() <= 1) throw(0);
    sort(begin(ps), end(ps));

    auto compare_y = [&](const Point &a, const Point &b) { return imag(a) < imag(b); };
    vector<Point> beet(ps.size());
    const Real INF = 1e18;

    function<Real(int, int)> rec = [&](int left, int right) {
        if(right - left <= 1) return INF;
        int mid = (left + right) >> 1;
        auto x = real(ps[mid]);
        auto ret = min(rec(left, mid), rec(mid, right));
        inplace_merge(begin(ps) + left, begin(ps) + mid, begin(ps) + right, compare_y);
        int ptr = 0;
        for(int i = left; i < right; i++) {
            if(abs(real(ps[i]) - x) >= ret) continue;
            for(int j = 0; j < ptr; j++) {
                auto luz = ps[i] - beet[ptr - j - 1];
                if(imag(luz) >= ret) break;
                ret = min(ret, abs(luz));
            }
            beet[ptr++] = ps[i];
        }
        return ret;
    };
    return rec(0, (int)ps.size());
}
} // namespace Geometry

using namespace Geometry;

struct Timer {
  private:
    chrono::high_resolution_clock::time_point start, end;

  public:
    Timer() { set(); }
    void set() { start = chrono::high_resolution_clock::now(); }
    int time() {
        end = chrono::high_resolution_clock::now();
        return chrono::duration_cast<chrono::milliseconds>(end - start).count();
    }
    bool before(double T) { return time() < (int)(T * 1000); }
    void print() { cerr << "elapsed time: " << (double)time() / 1000 << " sec" << endl; }
};

int main() {
    Timer timer;
    INT(n, k);
    double ok = 2e5, ng = 0;
    VEC2(int, x, y, n);
    Points P(n);
    rep(i, n) P[i] = Point(x[i], y[i]);
    vector<double> d(n), t(n);
    rep(i, n) d[i] = distance(Point(0, 0), P[i]);
    rep(i, n) t[i] = atan2(y[i], x[i]);
    rep(i, n) if(y[i] < 0) t[i] += 2 * PI;

    while(timer.before(3.5)) {
        double x = (ok + ng) / 2;
        map<double, int> mp;
        rep(i, n) {
            if(d[i] > 2 * x) continue;
            double theta = acos(d[i] / (2 * x));
            double l = t[i] - theta, r = t[i] + theta;
            if(l < 0)
                mp[0]++, mp[r]--, mp[l + PI * 2]++;
            else
                mp[l]++, mp[r]--;
        }
        bool flag = false;
        int c = 0;
        for(auto [_, kk] : mp) {
            c += kk;
            flag |= (c >= k);
        }
        (flag ? ok : ng) = x;
    }
    OUT(ok);
}