2227. E. 共同朋友

#pragma GCC optimize("Ofast,no-stack-protector")
#include<bits/stdc++.h>
#define int long long
#define quick ios::sync_with_stdio(0);cin.tie(0);
#define rep(x,a,b) for(int x=a;x<=b;x++)
#define repd(x,a,b) for(int x=a;x>=b;x--)
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define mp make_pair
#define eb emplace_back
#define sz(x) (int)(x.size())
#define lowbit(x) (x&-x)
using namespace std;
typedef pair<int,int> pii;
typedef complex<int> P;
#define X real()
#define Y imag()
void debug(){
    cout<<"\n";
}
template<class T,class ...U>
void debug(T a,U ...b){
    cout<<a<<" ",debug(b...);
}
const int N=2500+7;
const int INF=1e18;
vector<int> v[N];
int low[N];
int in[N];
int t=1;
int bridges=0;
//set<pii> Bridges;
void dfs(int x,int p=-1){
    low[x]=in[x]=t++;
    for(int i:v[x]){
        if(i==p) continue;
        if(in[i]) low[x]=min(low[x],in[i]);
        else{
            dfs(i,x);
            if(low[i]>in[x]){//(x,i) is bridge
                bridges++;
            }
            low[x]=min(low[x],low[i]);
        }
    }
}
struct Disjoint{
    int p[N];
    int s[N];
    void init(int n){
        rep(i,0,n) s[i]=1,p[i]=i;
    }
    int fp(int x){
        if(x!=p[x]) p[x]=fp(p[x]);
        return p[x];
    }
    void Union(int a,int b){
        a=fp(a);
        b=fp(b);
        if(a==b) return;
        if(s[a]<s[b]) swap(a,b);
        s[a]+=s[b];
        p[b]=a;
    }
    bool issame(int a,int b) {return fp(a)==fp(b);}
}st;
bool f[N][N];
signed main(){
    quick
    int n;
    cin>>n;
    st.init(n);
    rep(i,0,n-1){
        int di;
        cin>>di;
        while(di--){
            int x;
            cin>>x;
            f[i][x]=true;
        }
    }
    rep(i,0,n-1){
        rep(j,0,n-1){
            if(f[i][j]){
                st.Union(i,j);
                v[i].eb(j);
            }
        }
    }
    int ans=n*(n-1)/2;
    rep(i,0,n-1){
        rep(j,i+1,n-1){

            if(!st.issame(i,j)) ans--;
        }
    }
    //debug("now",ans);
    rep(i,0,n-1) {
        if(!in[i]) dfs(i);
    }
    ans-=bridges;
    cout<<ans<<"\n";

}