> #include<cstdio>
> #include<cstring>
> #include<algorithm>
> #include<cmath>
> using namespace std;
> int per[260000],n,m;
> double a[260000];
> struct node
> {
> 	int x,y;
> 	double w;
> }s[260000];
> bool cmp(node x,node y)
> {
> 	return x.w<y.w;
> }
> void init()
> {
> 	for(int i=0;i<=n;i++)
> 	per[i]=i;
> }
> int find(int x)
> {
> 	int i,j,t=x;
> 	while(t!=per[t])
> 	t=per[t];
> 	i=x;
> 	while(i!=t)
> 	{
> 		j=per[i];
> 		per[i]=t;
> 		i=j;
> 	}
> 	return t;
> }
> 
> bool join(int x,int y)
> {
> 	int fx=find(x);
> 	int fy=find(y);
> 	if(fx!=fy)
> 	{
> 		per[fx]=fy;
> 		return true ;
> 	}
> 	return false;
> }
> int main()
> {
> 	int i,j,n1;
> 	scanf("%d",&n1);
> 	while(n1--)
> 	{
> 		double x[600],y[600];
> 		scanf("%d%d",&m,&n);
> 		init();
> 		for(i=0;i<n;i++)
> 			scanf("%lf%lf",&x[i],&y[i]);
> 			int k=0;
> 			for(i=0;i<n;i++)
> 			{
> 				for(j=i+1;j<n;j++)
> 				{
> 					s[k].x=i;
> 					s[k].y=j;
> 					s[k++].w=sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
> 				}
> 			}
> 			sort(s,s+k,cmp);
> 			int t=0;
> 			for(int i=0 ; i<k ;  i++)
> 			{
> 				if(join(s[i].x,s[i].y))
> 				a[t++]=s[i].w;
> 			}
> 			printf("%.2f\n",a[t-m]);
> 	}
> 	return 0;
> }