int cur_max_dis = 0;

for(int start=0; start<N; start++){

memset(visited, 0, sizeof(visited));

queue< pii > Q;

pii init(start, 0);

Q.push(init);

while(!Q.empty()){

pii cur = Q.front();

Q.pop();

cur_max_dis = max(cur_max_dis, cur.second);

visited[cur.first] = 1;

int sz = G[cur.first].size();

for(int i=0; i<sz; i++){

int next = G[cur.first][i];

if(visited[next]==false){

pii next_node(next, cur.second+1);

Q.push(next_node);

}

}

}

}

return cur_max_dis;

ifstream fin("input.txt");

ofstream fout("output.txt");

fin>>T;

int ans = 0;

for(int spider = 0; spider <T; spider++){

fin>>N;

for(int i=0; i<MAXN; i++){

G[i].clear();

}

for(int i=0; i<N-1; i++){

int a, b;

fin>>a>>b;

a--,b--;

G[a].push_back(b);

G[b].push_back(a);

}

//cout<<"ready "<<endl;

int cur = work();

ans += cur;

}

fout<<ans<<endl;

return 0;