/**************************************************************

     Problem: 1821

     User: zhuohan123

     Language: C++

     Result: Accepted

     Time:136 ms

     Memory:18492 kb

 ****************************************************************/

 #include <iostream>

 #include <cstdio>

 #include <cmath>

 #include <algorithm>

 using namespace std;

 int f[];

 int gf(int p){return p==f[p]?p:f[p]=gf(f[p]);}

 struct point{double x,y;}p[];

 double dis(point a,point b){return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);}

 struct edge

 {

     int from,to;double c;

     friend bool operator<(edge a,edge b){return a.c<b.c;}

 }g[];int gnum;

 int main(int argc, char *argv[])

 {

     int n,k;scanf("%d%d",&n,&k);

     for(int i=;i<=n;i++)scanf("%lf%lf",&p[i].x,&p[i].y);

     for(int i=;i<=n;i++)f[i]=i;

     for(int i=;i<=n;i++)

         for(int j=;j<i;j++)

         {

             g[++gnum].from=i;

             g[gnum].to=j;

             g[gnum].c=dis(p[i],p[j]);

         }

     sort(g+,g+gnum+);

     for(int i=;i<=gnum;i++)

         if(gf(g[i].from)!=gf(g[i].to))

         {

             if(n>k){f[gf(g[i].from)]=gf(g[i].to);n--;}

             else {printf("%0.2lf\n",sqrt(g[i].c));return ;}

         }

     printf("0.00\n");

     return ;

 }