//Memory: 252K        Time: 16MS
 #include <iostream>
 #include <cstring>
 #include <cstdio>

 using namespace std;

 ;
 ;
 int edge[maxc][maxl];
 int ne[maxc];
 int match[maxl];
 bool vis[maxl];
 int n, t;
 int a, b;

 bool findPath(int start)
 {
     ; i < ne[start]; i++){
         int current = edge[start][i];
         if (vis[current]) continue;
         vis[current] = ;
         if ( !match[current] || findPath(match[current]) ){
             match[current] = start;
             return true;
         }
     }
     return false;
 }

 int solve()
 {
     memset(match, , sizeof(match));
     ;
     ; i <= ; i++) {
         memset(vis, , sizeof(vis));
         if (findPath(i)) cnt++;
     }
     return cnt;
 }

 void input()
 {
     memset(edge, , sizeof(edge));
     memset(ne, , sizeof(ne));
     ; i < n; i++){
         scanf("%d", &t);
         while (t--){
             scanf("%d%d", &a, &b);
             ) *  + b;
             edge[ class_num ][ ne[class_num]++ ] = i;
         }
     }
 }

 int main()
 {
     while ( ~scanf("%d", &n) ){
         input();
         int ans = solve();
         printf("%d\n", ans);
     }
     ;
 }