#include<bits/stdc++.h>
using namespace std;
int match[110], chw[110], tsp;
vector<int> G[310];
bool findmuniu(int x)
{
    for(int y : G[x])
    {
        if(chw[y] != tsp)
        {
            chw[y] = tsp;
            if((match[y] == 0) || (findmuniu(match[y]) == 1))
            {
                match[y] = x;
                return 1;
            }
        }
    }
    return 0;
}
int main()
{
    int n1, n2; scanf("%d", &n1); n2 = 7*12; // 构图：公牛是课程，母牛是上课时间（某天的某节课）
    for(int i = 1; i <= n1; i++)
    {
        int t; scanf("%d", &t);
        while(t--)
        {
            int p, q; scanf("%d%d", &p, &q);
            int y = (p-1)*12 + q;
            G[i].emplace_back(y);
        }
    }
    int ans = 0;
    memset(match, 0, sizeof(match));
    memset(chw, 0, sizeof(chw));
    for(int i = 1; i <= n1; i++)
    {
        tsp = i;
        if(findmuniu(i) == 1) ans++;
    }
    printf("%d", ans);
    return 0;
}