1 #include <bits/stdc++.h>
 2 #define LL long long
 3 using namespace std;
 4 inline int ra()
 5 {
 6     int x=0,f=1; char ch=getchar();
 7     while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
 8     while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
 9     return x*f;
10 }
11
12 const int mod=1e9+7;
13
14 LL g[20][20];
15 int n;
16 vector<pair<int , int > > orz[20];
17
18 int Gauss()
19 {
20     LL ans=1;
21     for (int i=1; i<n; i++)
22     {
23         for (int j=i+1; j<n; j++)
24             while (g[j][i])
25             {
26                 LL t=g[i][i]/g[j][i];
27                 for (int k=i; k<n; k++)
28                     g[i][k]=(g[i][k]-g[j][k]*t)%mod;
29                 swap(g[i],g[j]);
30                 ans=-ans;
31             }
32         ans=ans*g[i][i]%mod;
33         if (!ans) return 0;
34     }
35     return (ans+mod)%mod;
36 }
37
38 int main(int argc, char const *argv[])
39 {
40     n=ra();
41     for (int i=1; i<n; i++)
42     {
43         int m=ra();
44         for (int j=1; j<=m; j++)
45         {
46             int x=ra(),y=ra();
47             orz[i].push_back(make_pair(x,y));
48         }
49     }
50     int ans=0;
51     for (int i=0; i<1<<(n-1); i++)
52     {
53         int cnt=0; memset(g,0,sizeof(g));
54         for (int j=1; j<n; j++)
55             if ((i>>(j-1))&1)
56             {
57                 for (int k=0; k<orz[j].size(); k++)
58                 {
59                     int x=orz[j][k].first,y=orz[j][k].second;
60                     g[x][x]++; g[y][y]++;
61                     g[x][y]--; g[y][x]--;
62                 }
63                 cnt++;
64             }
65         if ((n-cnt)&1) ans=(ans+Gauss())%mod; else ans=(ans-Gauss()+mod)%mod;
66     }
67     printf("%d\n",ans);
68     return 0;
69 }