#include <bits/stdc++.h>

 using namespace std;

 const int maxn=+,maxm=+,maxq=1e6;

 const double eps=1e-;

 int c,n;

 double ans;

 inline int dcmp(double x){ if(fabs(x)<eps) return ; else return x>?:-; }

 struct pt{

     double x,y;

     pt(double x=,double y=):x(x),y(y){}

     pt operator + (const pt &a) const { return pt(x+a.x,y+a.y); }

     pt operator - (const pt &a) const { return pt(x-a.x,y-a.y); }

     pt operator * (const double &p) const { return pt(x*p,y*p); }

     pt operator / (const double &p) const { return pt(x/p,y/p); }

     pt normal(){ return pt(-y,x); }

     bool operator == (const pt &a) const { return !dcmp(x-a.x)&&!dcmp(y-a.y); }

     void read(){ scanf("%lf%lf",&x,&y); }

 }A[maxn];

 typedef pt vt;

 inline double dot(vt a,vt b){ return a.x*b.x+a.y*b.y; }

 inline double crs(vt a,vt b){ return a.x*b.y-a.y*b.x; }

 inline double len(vt a){ return sqrt(dot(a,a)); }

 struct sg{

     pt a,b;

     sg(){}

     sg(pt a,pt b):a(a),b(b){}

     bool on(const pt &p){ return !dcmp(crs(a-p,b-p))&&dcmp(dot(a-p,b-p))<; }

 }q[maxq];

 struct polygon{

     int cnt; pt p[maxm];

     bool in(const pt &a){

         int wn=;

         for(int i=;i<=cnt;i++){

             if(sg(p[i],p[i%cnt+]).on(a)) return true;

             int k=dcmp(crs(p[i%cnt+]-p[i],a-p[i]));

             int d1=dcmp(p[i].y-a.y);

             int d2=dcmp(p[i%cnt+].y-a.y);

             if(k>&&d1<=&&d2>) wn++;

             if(k<&&d2<=&&d1>) wn--;

         }

         return wn;

     }

 }land[maxn];

 struct node{

     pt p; double d;

     node(){}

     node(pt p,double d):p(p),d(d){}

 };

 inline pt get_l_int(pt p,vt v,pt q,vt w){

     vt u=p-q;

     double t=crs(w,u)/crs(v,w);

     return p+v*t;

 }

 inline node dis_to_sg(pt p,pt a,pt b){

     vt v1=b-a,v2=p-a,v3=p-b;

     if(dcmp(dot(v1,v2)<)) return node(a,len(v2));

     else if(dcmp(dot(v1,v3)>)) return node(b,len(v3));

     else return node(get_l_int(p,v1.normal(),a,v1),fabs(crs(v1,v2)/len(v1)));

 }

 inline node find(pt a){

     node t; t.d=<<;

     for(int i=;i<=c;i++){

         if(land[i].in(a)) return node(a,);

         for(int j=;j<=land[i].cnt;j++){

             node tmp=dis_to_sg(a,land[i].p[j],land[i].p[j%land[i].cnt+]);

             if(dcmp(tmp.d-t.d)<) t=tmp;

         }

     }

     ans=max(ans,t.d);

     return t;

 }

 inline void init(){

     scanf("%d%d",&c,&n);

     for(int i=;i<=n;i++) A[i].read();

     for(int i=;i<=c;i++){

         scanf("%d",&land[i].cnt);

         for(int j=;j<=land[i].cnt;j++) land[i].p[j].read();

     }

 }

 inline void solve(){

     int L=,R=;

     for(int i=;i<n;i++) q[R++]=sg(A[i],A[i+]);

     while(L!=R){

         sg t=q[L++]; if(L==maxq) L=;

         pt p1=find(t.a).p, p2=find(t.b).p,l=t.a,r=t.b,mid=(l+r)/;

         while(len(l-r)>1e-){

             mid=(l+r)/;

             if(len(mid-p1)<len(mid-p2)) l=mid;

             else r=mid;

         }

         double tmp=min(len(mid-p1),len(mid-p2));

         if(ans+0.0001<tmp){

             q[R++]=sg(t.a,mid); if(L==maxq) L=;

             q[R++]=sg(mid,t.b); if(L==maxq) L=;

         }

     }

     printf("%.2lf\n",ans);

 }

 int main(){

     init();

     solve();

     return ;

 }