/************************************************
Author :DarkTong
Created Time :2016/7/31 15:38:05
File Name :Poj_2339.cpp
*************************************************/
//#include <bits/stdc++.h>
#include <cstdio>
#include <cstring>
using namespace std;
#define max(a, b) a>b?a:b
const int maxn = 300+10;
int w[maxn][maxn], Left[maxn], n, m;
bool used[maxn];
bool match(int j)
{
for(int i=1;i<=n;++i)if(w[i][j]&&!used[i])
{
used[i]=true;
if(!Left[i]||match(Left[i]))
{
Left[i]=j;
return true;
}
}
return false;
}
int hungary()
{
int res=0;
memset(Left, 0, sizeof(Left));
for(int i=1;i<=m;++i)
{
memset(used, 0, sizeof(used));
if(match(i)) res++;
}
return res;
}
int main()
{
int T, cas=1;
while(scanf("%d", &m)==1)
{
memset(w, 0, sizeof(w));
int p, q, t;
for(int i=1;i<=m;++i)
{
scanf("%d", &t);
for(int j=1;j<=t;++j)
{
scanf("%d%d", &p, &q);
w[(p-1)*12+q][i]=1;
n = max((p-1)*12+q, n);
}
}
printf("%d\n", hungary());
}
return 0;
}