#include <bits/stdc++.h>
using namespace std;

template<typename T>
struct Point{
    public:
    T x,y;
    Point() : x(0),y(0) {}
    Point(T a,T b) : x(a),y(b) {}
    Point &operator=(const Point &b) = default;
    Point operator+(const Point &b){return Point(x+b.x,y+b.y);}
    Point operator-(const Point &b){return Point(x-b.x,y-b.y);}
    Point operator+=(const Point &b){return *this=*this+b;}
    Point operator-=(const Point &b){return *this=*this-b;}
    bool operator==(const Point &b){return x==b.x && y==b.y;}
    bool operator!=(const Point &b){return x!=b.x || y!=b.y;}
    bool operator<(const Point &b){
        if(x == b.x) return y < b.y;
        else return x < b.x; 
    }
    bool operator<=(const Point &b){return (*this) < b || (*this) == b;}
    bool operator>(const Point &b){return !((*this) <= b);}
    bool operator>=(const Point &b){return !((*this) < b);}

    friend T inner(const Point a,const Point b){return a.x*b.x+a.y*b.y;}
    friend T cross(const Point a,const Point b){return a.x*b.y-a.y*b.x;}
    friend T twodist(const Point a,const Point b){return sqrtl((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));}
};
template<typename T>
istream &operator>>(istream &is,Point<T> &a){
    is >> a.x >> a.y;
    return is;
}
template<typename T>
ostream &operator<<(ostream &os,Point<T> &a){
    os << a.x << " " << a.y;
    return os;
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N,K; cin >> N >> K;
    vector<Point<double>> P(N);
    for(auto &p : P) cin >> p;

    int n2 = 1<<N;
    vector<vector<vector<double>>> dp(n2,vector<vector<double>>(N,vector<double>(K,1e100)));
    for(int i=0; i<N; i++) dp.at(1<<i).at(i).at(K-1) = twodist({0.0,0.0},P.at(i));
    for(int i=1; i<n2; i++){
        for(int k=0; k<N; k++){
            if(!(i&(1<<k))) continue;
            int left = i-(1<<k);
            for(int l=0; l<N; l++){
                if(!(i&(1<<l))) continue;

                double mind = dp.at(left).at(l).at(0);    
                for(int m=0; m<K-1; m++){
                    dp.at(i).at(k).at(m) = min(dp.at(i).at(k).at(m),dp.at(left).at(l).at(m+1)+twodist(P.at(k),P.at(l)));
                    mind = min(mind,dp.at(left).at(l).at(m+1));
                }
                dp.at(i).at(k).at(K-1) = min(dp.at(i).at(k).at(K-1),mind+twodist({0,0},P.at(l))+twodist({0,0},P.at(k)));
            }
        }
    }

    double answer = 1e100;
    for(int i=0; i<N; i++){
        double nowd = twodist({0,0},P.at(i));
        for(int k=0; k<K; k++) answer = min(answer,dp.at(n2-1).at(i).at(k)+nowd);
    }
    cout << fixed << setprecision(20) << answer << endl;
}