#ifndef LOCAL
#pragma GCC optimize("Ofast,no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,mmx,tune=native")
#endif //LOCAL

#define _SCL_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#define _CRT_SECURE_NO_WARNINGS

#pragma comment(linker, "/STACK:256000000")

//#define push_back pb
#define first x
#define second y

#include <cassert>
#include <ciso646>
#include <climits>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <array>
#include <bitset>
#include <deque>
#include <forward_list>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include <algorithm>
#include <complex>
#include <functional>
#include <initializer_list>
#include <iterator>
#include <limits>
#include <locale>
#include <numeric>
#include <regex>
#include <string>
#include <utility>
#include <fstream>
#include <iostream>
#include <sstream>
#include <iomanip>
#include <random>
#include <memory>
#include <chrono>

#ifdef LOCAL
//#include <vld.h>
#endif //LOCAL
using namespace std;

//typedef __int128_t ll;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef long double ld;

#define speedup cout.tie(nullptr);cin.tie(nullptr);ios_base::sync_with_stdio(false)
#define coutdouble cout<<setprecision(20);cout<<fixed

#define all(v) (v).begin(),(v).end()
#define sz(v) (int)(v).size()

#ifdef LOCAL
mt19937 rd(57322);
#else
mt19937 rd((uint)chrono::steady_clock::now().time_since_epoch().count());
#endif
/*------CommentInInteractive--------*/
#ifndef LOCAL
#define endl '\n'
#endif //LOCAL
/*----------------------------------*/
const int INF = 1000 * 1000 * 1000 + 322;
const ll LLINF = 2LL * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL * 1000LL + 57;
constexpr uint MOD = 1000 * 1000 * 1000 + 7;
constexpr uint FFT_MOD = 998244353;
const int P1E6 = 1336337;
const int P1E3 = 1009;
const ll P1E14 = 100000000000031;
const ll P1E17 = 100000000000000003;
const ld PI = acosl(-1.);//3.1415926535897932384626433832795
const ld EPS = 1e-6;
/*------------------------------------------------IO_OPERATORS---------------------------------------------*/
template<typename T, typename U> inline ostream &operator << (ostream &_out, const pair<T, U> &_p) { _out << _p.first << " " << _p.second; return _out; }
template<typename T, typename U> inline istream &operator >> (istream &_in, pair<T, U> &_p) { _in >> _p.first >> _p.second; return _in; }
template<typename T> inline ostream &operator << (ostream &_out, const vector<T> &_v) { if (_v.empty()) return _out; _out << _v.front(); for (auto _it = ++_v.begin(); _it != _v.end(); ++_it) _out << ' ' << *_it; return _out; }
template<typename T> inline istream &operator >> (istream &_in, vector<T> &_v) { for (auto &_i : _v) _in >> _i; return _in; }
template<typename T> inline ostream &operator << (ostream &_out, const set<T> &_s) { if (_s.empty()) return _out; _out << *_s.begin(); for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) _out << ' ' << *_it; return _out; }
template<typename T> inline ostream &operator << (ostream &_out, const multiset<T> &_s) { if (_s.empty()) return _out; _out << *_s.begin(); for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) _out << ' ' << *_it; return _out; }
template<typename T> inline ostream &operator << (ostream &_out, const unordered_set<T> &_s) { if (_s.empty()) return _out; _out << *_s.begin(); for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) _out << ' ' << *_it; return _out; }
template<typename T> inline ostream &operator << (ostream &_out, const unordered_multiset<T> &_s) { if (_s.empty()) return _out; _out << *_s.begin(); for (auto _it = ++_s.begin(); _it != _s.end(); ++_it) _out << ' ' << *_it; return _out; }
template<typename T, typename U> inline ostream &operator << (ostream &_out, const map<T, U> &_m) { if (_m.empty()) return _out; _out << '(' << _m.begin()->first << ": " << _m.begin()->second << ')'; for (auto _it = ++_m.begin(); _it != _m.end(); ++_it) _out << ", (" << _it->first << ": " << _it->second << ')'; return _out; }
template<typename T, typename U> inline ostream &operator << (ostream &_out, const unordered_map<T, U> &_m) { if (_m.empty()) return _out; _out << '(' << _m.begin()->first << ": " << _m.begin()->second << ')'; for (auto _it = ++_m.begin(); _it != _m.end(); ++_it) _out << ", (" << _it->first << ": " << _it->second << ')'; return _out; }
/*--------------------------------------------------IO_FILES-----------------------------------------------*/
const char * infile =
#ifdef LOCAL
"input.txt"
#else
""
#endif //LOCAL
;
const char * outfile =
#ifdef LOCAL
""
#else
""
#endif //LOCAL
;

/*-------------------------------------------------ALLOCATOR----------------------------------------------*/
//#define ALLOC_LOCAL
#ifdef ALLOC_LOCAL
const int ML_ = 450;
char mem_[ML_ * 1024 * 1024];
size_t _ptr = 0, _magic = 21323400;
void * operator new(size_t cnt) { if (_ptr + cnt < sizeof mem_) { _ptr += cnt; return  mem_ + _ptr - cnt; } else { assert(false);  _ptr = cnt + _magic; return mem_ + _magic; } }
void operator delete(void *) {}
#endif //ALLOC_LOCAL
/*-----------------------------------------------------MATH------------------------------------------------*/
inline ll gcd(ll a, ll b) { while (b) { a %= b; swap(a, b); } return a; }
inline ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
inline int pwm(ll xx, ll pow, int MD) { if (pow < 0) { pow = pow % (MD - 1) + MD - 1; } ll mlt = 1; while (pow) { if (pow & 1) { mlt *= xx; mlt %= MD; } xx *= xx; pow >>= 1; xx %= MD; } return (int)mlt; }
inline ll gcdex(ll a, ll b, ll &x, ll &y) { if (b == 0) { x = 1; y = 0; return a; } ll xx, yy; ll gc = gcdex(b, a % b, yy, xx); x = xx; y = yy - (a / b) * xx; return gc; }
inline int inv(ll r, int _mod) { return pwm(r % _mod, _mod - 2, _mod); }
/*-----------------------------------------------------CODE------------------------------------------------*/


vector<ld> slvsq(const vector<ld>& cf) {
	assert(sz(cf) == 3);
	ld det = cf[1] * cf[1] - 4 * cf[0] * cf[2];
	if (det < 0) {
		return{};
	}
	return{ (-cf[1] - sqrtl(det)) / (2 * cf[0]), (-cf[1] + sqrtl(det)) / (2 * cf[0]) };
}

ld get_t(const pair<pair<ll, ll>, ll>& pp, ld x, ld y) {
	return pp.y * hypotl(pp.x.x - x, pp.x.y - y);
}

ld checkpt(const vector<pair<pair<ll, ll>, ll>>& v, ld x, ld y, int k) {
	vector<ld> dsts;
	for (const auto &pp : v) {
		dsts.push_back(get_t(pp, x, y));
	}
	nth_element(dsts.begin(), dsts.begin() + k - 1, dsts.end());
	return dsts[k - 1];
}

ld calc(const vector<pair<pair<ll, ll>, ll>>& v, int i, int j, int k, int need) {
	if (v[i].y == v[j].y && v[i].y == v[k].y) {
		ld a0 = 2 * (v[j].x.y * v[j].y * v[j].y - v[i].x.y * v[i].y * v[i].y);
		ld b0 = 2 * (v[j].x.x * v[j].y * v[j].y - v[i].x.x * v[i].y * v[i].y);
		ld c0 = (v[i].y * v[i].y * v[i].x.x * v[i].x.x + v[i].y * v[i].y * v[i].x.y * v[i].x.y - v[j].y * v[j].y * v[j].x.x * v[j].x.x - v[j].y * v[j].y * v[j].x.y * v[j].x.y);

		ld a1 = 2 * (v[k].x.y * v[k].y * v[k].y - v[j].x.y * v[j].y * v[j].y);
		ld b1 = 2 * (v[k].x.x * v[k].y * v[k].y - v[j].x.x * v[j].y * v[j].y);
		ld c1 = (v[j].y * v[j].y * v[j].x.x * v[j].x.x + v[j].y * v[j].y * v[j].x.y * v[j].x.y - v[k].y * v[k].y * v[k].x.x * v[k].x.x - v[k].y * v[k].y * v[k].x.y * v[k].x.y);
		
		if (abs(a0) < EPS && abs(a1) < EPS) {
			return INF;
		}
		if (abs(a0) < EPS) {
			swap(a0, a1);
			swap(b0, b1);
			swap(c0, c1);
		}
		b0 /= a0;
		c0 /= a0;
		a0 = 1;
		b1 -= a1 * b0;
		c1 -= a1 * c0;
		a1 = 0;

		if (abs(b1) < EPS) {
			return INF;
		}

		ld x = -c1 / b1;
		ld y = -b0 * x - c0;

		ld t1 = get_t(v[i], x, y);
		ld t2 = get_t(v[j], x, y);
		ld t3 = get_t(v[k], x, y);
		if (max(abs(t1 - t2), abs(t2 - t3)) > EPS) {
			while (true) {
				t1 += 1;
			}
		}

		return checkpt(v, x, y, need);
	} else if (v[i].y != v[j].y && v[i].y != v[k].y){
		swap(i, j);
	} else if (v[k].y != v[j].y && v[i].y != v[k].y) {
		swap(j, k);
	}
	ld dv0 = v[i].y * v[i].y - v[j].y * v[j].y;
	assert(abs(dv0) > EPS);
	ld al0 = 2 * (v[j].x.y * v[j].y * v[j].y - v[i].x.y * v[i].y * v[i].y) / dv0;
	ld bt0 = 2 * (v[j].x.x * v[j].y * v[j].y - v[i].x.x * v[i].y * v[i].y) / dv0;
	ld gm0 = (v[i].y * v[i].y * v[i].x.x * v[i].x.x + v[i].y * v[i].y * v[i].x.y * v[i].x.y - v[j].y * v[j].y * v[j].x.x * v[j].x.x - v[j].y * v[j].y * v[j].x.y * v[j].x.y) / dv0;

	ld dv1 = v[j].y * v[j].y - v[k].y * v[k].y;
	assert(abs(dv1) > EPS);
	ld al1 = 2 * (v[k].x.y * v[k].y * v[k].y - v[j].x.y * v[j].y * v[j].y) / dv1;
	ld bt1 = 2 * (v[k].x.x * v[k].y * v[k].y - v[j].x.x * v[j].y * v[j].y) / dv1;
	ld gm1 = (v[j].y * v[j].y * v[j].x.x * v[j].x.x + v[j].y * v[j].y * v[j].x.y * v[j].x.y - v[k].y * v[k].y * v[k].x.x * v[k].x.x - v[k].y * v[k].y * v[k].x.y * v[k].x.y) / dv1;

	ld cf1 = al0 - al1;
	ld cf2 = bt0 - bt1;
	ld cf3 = gm0 - gm1;

	vector<pair<ld, ld>> tocheck;
	if (abs(cf1) > EPS) {
		ld kk = -cf2 / cf1;
		ld bb = -cf3 / cf1;
		vector<ld> quad = { kk * kk + 1, 2 * kk * bb + al0 * kk + bt0, gm0 + bb * bb + al0 * bb };
		auto xx = slvsq(quad);
		for (auto &x : xx) {
			//cerr << quad[0] * x * x + quad[1] * x + quad[2] << endl;
			//assert(abs(quad[0] * x * x + quad[1] * x + quad[2]) < EPS);
			tocheck.push_back({ x, kk * x + bb });
		}
	} else if (abs(cf2) > EPS) {
		ld x = -cf3 / cf2;
		vector<ld> quad = { 1, al0, bt0 * x + gm0 + x * x };
		auto yy = slvsq(quad);
		for (auto &y : yy) {
			tocheck.push_back({ x, y });
		}
	} else {
		assert(abs(cf3) > EPS);
	}
	ld ans = INF;
	for (auto& p : tocheck) {
		ld x = p.x;
		ld y = p.y;

		ld t1 = get_t(v[i], x, y);
		ld t2 = get_t(v[j], x, y);
		ld t3 = get_t(v[k], x, y);
		//if (max(abs(t1 - t2), abs(t2 - t3)) > EPS) {
		//	assert(false);
		//}

		ans = min(ans, checkpt(v, x, y, need));
	}
	return ans;
}

inline void solve() {
	int n, k;
	cin >> n >> k;
	vector<pair<pair<ll, ll>, ll>> v(n);
	cin >> v;
	if (k == 1) {
		cout << 0 << endl;
		return;
	}
	if (k == 2) {
		ld tt = INF;
		for (int i = 0; i < n; ++i) {
			for (int j = i + 1; j < n; ++j) {
				ld dst = hypot(v[i].x.x - v[j].x.x, v[i].x.y - v[j].x.y);
				tt = min(tt, v[i].y * v[j].y * dst / (v[i].y + v[j].y));
			}
		}
		cout << tt << endl;
		return;
	}
	ld tt = INF;
	for (int i = 0; i < n; ++i) {
		for (int j = i + 1; j < n; ++j) {
			for (int kk = j + 1; kk < n; ++kk) {
				tt = min(tt, calc(v, i, j, kk, k));
			}
		}
	}
	for (int i = 0; i < n; ++i) {
		for (int j = i + 1; j < n; ++j) {
			ld cf = ld(v[j].y) / (v[i].y + v[j].y);
			ld x = v[i].x.x + (v[j].x.x - v[i].x.x) * cf;
			ld y = v[i].x.y + (v[j].x.y - v[i].x.y) * cf;
			tt = min(tt, checkpt(v, x, y, k));
		}
	}
	cout << tt << endl;
}

int main() {

	if (*infile != '\0')
		(void)freopen(infile, "r", stdin);
	if (*outfile != '\0')
		(void)freopen(outfile, "w", stdout);

	speedup;
	coutdouble;


	//int tst = 1;
	//srand(time(NULL));
	//cin >> tst;
	//scanf("%d", &tst);
	//while (tst-- > 0) {
	//while(true) {
	solve();
	//if ((tst & 0xF) == 0) {
	//cerr << "ok\n";
	//}
	//cerr << "/*-----------------*/\n";
	//}

#ifdef LOCAL
	cerr << "Time: " << (ld)clock() / CLOCKS_PER_SEC << endl;
	while (true);
#endif // LOCAL

	return 0;
}

Measured memory_bytes: 512