#include <cstdio>
#include <vector>
#include <complex>
#include <algorithm>
using namespace std;

#define N 30
#define eps 1e-8
typedef complex<double> P;
vector<P> ls[N];
int n,cols[N],g[N][N],cc_id[N];
int ord[N],deg[N],min_deg;

int sort_by_deg(int a, int b) {
  if (deg[a]!=deg[b]) return deg[a]>deg[b];
  return 0;
}

double det(P p, P q) { return imag(conj(p)*q); }
double dot(P p, P q) { return real(conj(p)*q); }

int ccw(P a, P b, P c) {
  b -= a; c -= a;
  if (det(b,c)>eps) return 1;         
  if (det(b,c)<-eps) return -1;       
  if (dot(b,c)<-eps) return 2;        
  if (norm(b)<norm(c)-eps) return -2; 
  return 0;                           
}

int intersect(P p1, P p2, P p3, P p4) {
  return ccw(p1,p2,p3)*ccw(p1,p2,p4)<=0&&ccw(p3,p4,p1)*ccw(p3,p4,p2)<=0;
}

int subway_intersect(int a, int b) {
  for (int i=0;i<ls[a].size()-1;++i)
    for (int j=i+2;j<ls[a].size()-1;++j) 
      if (intersect(ls[a][i],ls[a][i+1],ls[a][j],ls[a][j+1]))
	assert(!"self intersection");

  for (int i=0;i<(int)ls[a].size()-1;++i)
    for (int j=0;j<(int)ls[b].size()-1;++j) 
      if (intersect(ls[a][i],ls[a][i+1],ls[b][j],ls[b][j+1]))
	return 1;
  return 0;
}

void dfs(int pos, int id) {
  if (cc_id[pos]!=-1) return;
  cc_id[pos]=id;
  for (int i=0;i<n;++i)
    if (g[pos][i])
      dfs(i,id);
}

void solve(int cur, int col_num, int id, int& cur_ans) {
  if (col_num>=cur_ans) return;
  if (cur==n) {
    cur_ans<?=col_num;
    return;
  }
  int pos=ord[cur];
  if (cc_id[pos]!=id) {
    solve(cur+1,col_num,id,cur_ans);
    return;
  }
   
  int ng[N]={};
  for (int i=0;i<n;++i)
    if (g[pos][i]&&cols[i]!=-1)
      ng[cols[i]]=1;
  for (int i=0;i<col_num;++i)
    if (!ng[i]) {
      cols[pos]=i;
      solve(cur+1,col_num,id,cur_ans);
      cols[pos]=-1;
    }
  cols[pos]=col_num;
  solve(cur+1,col_num+1,id,cur_ans);
  cols[pos]=-1;
}

int main() {
  while(scanf("%d",&n),n) {
    if (n>22) {
      assert(!"too many vertices");
    }
    for (int i=0;i<n;++i) {
      ls[i].clear();
      int num; scanf("%d",&num);
      if (num<=1||num>30) assert(!"invalid number of stations");
      for (int j=0;j<num;++j) {
	double x,y; scanf("%lf%lf",&x,&y);
	ls[i].push_back(P(x,y));
      }
    }
    memset(g,0,sizeof(g));
    for (int i=0;i<n;++i)
      for (int j=i+1;j<n;++j) 
	if (subway_intersect(i,j)) 
	  g[i][j]=g[j][i]=1;

    memset(deg,0,sizeof(deg));
    for (int i=0;i<n;++i)  
      for (int j=0;j<n;++j)
	if (g[i][j])
	  ++deg[i];

    for (int i=0;i<n;++i) ord[i]=i;
    sort(ord,ord+n,sort_by_deg);

    int cc_num=0;
    memset(cc_id,-1,sizeof(cc_id));
    for (int i=0;i<n;++i)
      if (cc_id[i]==-1)
	dfs(i,cc_num++);

    int ans=0;
    memset(cols,-1,sizeof(cols));
    for (int i=0;i<cc_num;++i) {
      int cur_ans=INT_MAX;
      solve(0,0,i,cur_ans);
      ans>?=cur_ans;
    }
    printf("%d\n",ans);
  }
}