Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

C++: /**Function Template**/
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> pint;
const int MAX = 510000;
const int MOD = 1000000007;
#define rep(i, n) for(ll i = ll(0); i < ll(n); i++)
#define Rep(i, n) for(ll i = ll(1); i < ll(n); i++)
#define ALL(a)  (a).begin(),(a).end()
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define PI 3.14159265358979323846
#define ifYN(x) cout<<(x?"Yes":"No")<<"\n" 
ll fac[MAX], finv[MAX], inv[MAX];


template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

bool palindrome(string s){
  bool flag=true;
  rep(i,(ll)s.size()) if(s[i]!=s[s.size()-1-i]) flag=false;
  return flag;
}

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (ll i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }

}
ll Len(ll n) {
  ll s=0;
  while(n!=0) s++, n/=10;
  return s;
}


ll Sint(ll n) {
  ll ans=0;
  while(n!=0) ans+=n%10,n/=10;
  return ans;
}

ll Svec(vector<ll> v){
  ll n=0;
  rep(i,(ll)v.size()) n+=v[i];
  return n;
}


ll GCD(ll a,ll b) {
  return b ? GCD(b,a%b) : a;
}


ll LCM(ll a,ll b){
  return a/GCD(a,b)*b;
}


ll Factorial(ll n){
  ll m=1;
  while(n>=1) m*=n,n--;
  return m;
}

void runlength(string s,vector<pair<char,ll>> &p){
  ll x=1;
  if(s.size()==1){
    p.push_back(pair<char,ll>(s[0],1));
  }
  rep(i,(ll)s.size()-1){
    if(s[i]==s[i+1]){
      x++;
      if(i==(ll)s.size()-2){
        p.push_back(pair<char,ll>(s[i],x));
      }
    }else{
      p.push_back(pair<char,ll>(s[i],x));
      x=1;
      if(i==(ll)s.size()-2){
        p.push_back(pair<char,ll>(s[s.size()-1],x));
      }
    }
  }
}

ll COM(ll n,ll k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

ll modpow(ll a, ll n, ll mod) {
    ll res = 1;
    while (n > 0) {
        if (n & 1) res = res * a % mod;
        a = a * a % mod;
        n >>= 1;
    }
    return res;
}

string Toupper(string s){
  string ans="";
  rep(i,s.size()){
    if('a'<=s[i] && s[i]<='z') ans+=(char)s[i]-32;
    else ans+=s[i];
  }
  return ans;
}
string Tolower(string s){
  string ans="";
  rep(i,s.size()){
    if('A'<=s[i] && s[i]<='Z') ans+=(char)s[i]+32;
    else ans+=s[i];
  }
  return ans;
}

void dis(vector<ll> v){ rep(i,v.size()) cout<<v[i]<<endl; }

void dis2(vector<vector<ll>> v){
  rep(i,v.size()){
    rep(j,v[0].size()) cout<<v[i][j]<<' ';
    cout<<endl;
  }
}

const int MAX_N=100010;
vector<bool> sieve_of_eratosthenes(){
  vector<bool> isPrime(MAX_N+1,true);
  /* isPrime[1]=false; */
  for(int i=2;i<=MAX_N;i++){
    if(isPrime[i]){
      for(int j=2*i;j<=MAX_N;j+=i){
        isPrime[j]=false;
      }
    }
  }
  return isPrime;
}

vector<pint> prime_factorize(ll n){
  vector<pint> ans;
  for(ll p=2;p<=sqrt(n);p++){
    if(n%p!=0) continue;
    ll cnt=0;
    while(n%p==0){
      n/=p;
      cnt++;
    }
    ans.push_back(make_pair(p,cnt));
  }
  if(n!=1) ans.push_back(make_pair(n,1));
  return ans;
}

/*bool cmp(pint a, pint b) { return a.second < b.second; }*/
vector<ll> g[110];
vector<ll> s(110,0),e(110,0);
vector<bool> reached(110,false);
ll cnt=0;
void dfs(ll n){
  if(reached[n]) return;
  cnt++;
  reached[n]=true;
  s[n]=cnt;
  for(auto c:g[n]) dfs(c);
  cnt++;
  e[n]=cnt;
}

/*↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓*/
int main() {
  IOS;
  ll n;cin>>n;
  rep(i,n){
    ll a,b;cin>>a>>b;a--;
    rep(j,b){
      ll c;cin>>c;c--;
      g[a].push_back(c);
    }
  }
  rep(i,n) if(s[i]==0) dfs(i);
  rep(i,n) cout<<i+1<<' '<<s[i]<<' '<<e[i]<<endl;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>

using namespace std;

bool check[109];
int d[109], f[109];
int n, t=0;
vector<int> G[109];

void dfs(int n){
  check[n] = true;
  d[n] = ++t;
  for(int i=0;i<G[n].size();i++){
    if(!check[G[n][i]])dfs(G[n][i]);
  }
  f[n] = ++t;
}

int main(){
  memset(check, false, sizeof(check));
  cin >> n;
  for(int i=0;i<n;i++){
    int u, k, v;
    cin >> u >> k;
    for(int i=0;i<k;i++){
      cin >> v;
      G[u].push_back(v);
      sort(G[u].begin(), G[u].end());
    }
  }
  for(int i=1;i<=n;i++){
    if(!check[i])dfs(i);
  }
  for(int i=1;i<=n;i++)cout << i << ' ' <<  d[i] << ' ' << f[i] << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(),(x).end()
const double PI = acos(-1);
const ll MOD = 1000000007;
using Graph = vector<vector<int>>;

int n;
int t = 0;
Graph G;
vector<int> color, d, f;

void dfs(int u) {
  t++;
  d[u] = t;
  rep(i,n) {
    if (d[i] != 0) continue;
    if (G[u][i]) {
      dfs(i);
    }
  }
  t++;
  f[u] = t;
  return;
}

int main() {
  cin >> n;
  G.resize(n, vector<int>(n));
  d.resize(n);
  f.resize(n);
  rep(i,n) {
    int u,k; cin >> u >> k;
    u--;
    rep(j,k) {
      int v; cin >> v;
      v--;
      G[u][v] = 1;
    }
  }

  rep(i,n) {
    if (d[i] == 0) dfs(i);
  }

  rep(i,n) cout << i+1 << " " << d[i] << " " << f[i] << endl;
}