Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	ans := make([][2]int, N)
	time := 0
	found := make(map[int]bool)
	var dfs func(cur int)
	dfs = func(cur int) {
		time++
		ans[cur][0] = time
		found[cur] = true
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if !found[next] {
				dfs(G[cur][i])
			}
		}
		time++
		ans[cur][1] = time
	}
	for i := 0; i < N; i++ {
		if !found[i] {
			dfs(i)
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprint(wtr, i+1)
		for j := 0; j < 2; j++ {
			fmt.Fprint(wtr, " ")
			fmt.Fprint(wtr, ans[i][j])
		}
		fmt.Fprintln(wtr)
	}
	wtr.Flush()
}

C++: #include <algorithm>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long ll;

#define MOD 1000000007

vector<int> g[100];
vector<bool> visit(100);
vector<int> d(100), f(100);

int cnt = 0;

void dfs(int v) {
  d[v] = ++cnt;
  visit[v] = true;
  for (auto u : g[v]) {
    if (!visit[u]) {
      dfs(u);
    }
  }
  f[v] = ++cnt;
}

int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    int u, k;
    cin >> u >> k;
    u--;
    for (int j = 0; j < k; ++j) {
      int v;
      cin >> v;
      v--;
      g[u].push_back(v);
    }
  }
  for (int i = 0; i < n; ++i) {
    if (!visit[i]) {
      dfs(i);
    }
  }
  for (int i = 0; i < n; ++i) {
    cout << i + 1 << " " << d[i] << " " << f[i] << endl;
  }
  return 0;
}

C++: #include<stdio.h>

#define WHITE 0   // not visited yet.
#define GRAY 1    // visited, but not completed.
#define BLACK 2   // search completed.

int G[101][101];        // adjacency list.
int color[101];         // visited/completed sign.
int n;                  // size.
int d[101], f[101], t;  // first visit time/complete time.

void search_loop(int i) 
{
    int next;
    d[i] = ++t;
    color[i] = GRAY;  // first visited.

    for(next = 1; next <= n; next++){
        if(i == next && G[i][i] > 0) break;   // if self-looped, through.
        if(G[i][next] > 0 && color[next] == WHITE){  // if not visited yet, visit.
            search_loop(next);
        }
    }
    f[i] = ++t;
    color[i] = BLACK;  // completed. 

    return;
}

void dfs()
{
    int i;
    for(i = 1; i <= n; i++) color[i] = WHITE;  // initialize.
    t = 0;

    for(i = 1; i <= n; i++) if(color[i] == WHITE) search_loop(i);

    for(i = 1; i <= n; i++) printf("%d %d %d", i, d[i], f[i]);

    return ;
}

int main()
{
    int i, j, k, e;
    scanf("%d", &n);
    for(i = 1; i <= n; i++){
        for(j = 1; j <= n; j++){ G[i][j] = 0; } }

    do{
        scanf("%d %d", &i, &e);
        for(j = 1; j <= e; j++){
            scanf("%d", &k);
            G[i][k] = 1;
        }
    }while(i < n);

    dfs();
    return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
static const int N=100;
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;

int n,M[N][N];
int color[N],d[N],f[N],tt;
int nt[N];

//u?????£??\??????v?????????????????????
int next(int u){
	for (int v = 0; v < n; ++v) {
		nt[u]=v+1;
		if(M[u][v])return v;
	}
	return -1;
}

//?????????????????¨????????±???????????¢?´¢
void dfs_visit(int r){
	for (int i = 0; i < n; ++i) {nt[i]=0;}
	stack<int> S;
	S.push(r);
	color[r]=GRAY;
	d[r]=++tt;
	while(!S.empty()){
		int u=S.top();
		int v=next(u);
		if(v!=-1){
			if(color[v]==WHITE){
				color[v]=GRAY;
				d[v]=++tt;
				S.push(v);
			}
		}else{
			S.pop();
			color[u]=BLACK;
			f[u]=++tt;
		}
	}
}

void dfs(){
	//?????????
	for (int i = 0; i < n; ++i) {
		color[i]=WHITE;
		nt[i]=0;
	}
	tt=0;
	//????¨???????u????§??????¨????????±???????????¢?´¢
	for (int u = 0; u < n; ++u) {
		if(color[u]==WHITE)dfs_visit(u);
	}
	for (int i = 0; i < n; ++i) {
		cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
	}
}


int main(){
	int u,k,v;
	cin>>n;
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n; ++j) {
			M[i][j]=0;
		}
	}
	for (int i = 0; i < n; ++i) {
		cin>>u>>k;
		u--;
		for (int j = 0; j < k; ++j) {
			cin>>v;
			v--;
			M[u][v]=1;
		}
	}
	dfs();
	return 0;
}

C++: #include<iostream>
using namespace std;
#define MAX 100

int mat[MAX][MAX] = {};
int n, tt = 0, d[MAX] = {}, f[MAX] = {};
bool c[MAX];

void dfs_visit(int u){
    c[u] = true;
    d[u] = ++tt;
    for(int i = 0; i < n; i++){
        if(mat[u][i] == 0)  continue;
        if(!c[i])   dfs_visit(i);
    }
    f[u] = ++tt;
}

void dfs(){
    for(int i = 0; i < n; i++){
        if(!c[i])   dfs_visit(i);
    }

    for(int i = 0; i < n; i++){
        cout << (i+1) << " " << d[i] << " " << f[i] << endl;
    }
}

int main(){
    cin >> n;
    
    for(int i = 0; i < n; i++){
        int x, k, y;
        cin >> x >> k;
        while(k-- > 0){
            cin >> y;
            mat[x-1][y-1] = 1;
        }
    }

    dfs();
    return 0;
}

C++: #include <iostream>
using namespace std;
int n,a[100][100],b[100],c[100],d[100],cnt=1;
void DepthFirstSearch(int now){
  b[now]=1;
  c[now]=cnt;
  cnt++;
    for(int i=0;i<n;i++){
        if(a[now][i] && b[i]!=1){
            DepthFirstSearch(i);
            cnt++;
        }
    }
  d[now]=cnt;
}
int main(){
  
  int u,m,num;
  cin>>n;
  for(int i = 0;i < n;i++){
    cin>>u>>m;
    for(int j = 0;j < m;j++){
      cin >> num;
      a[u-1][num-1]=1;
    }
  }
    for(int i=0;i<n;i++){
       if(b[i]!=1){
         DepthFirstSearch(i);
         cnt++;
       }
    }
  
    for(int i=0;i<n;i++){
        cout<< i+1 << " " << c[i] << " " << d[i]<<endl;
    }
  return 0;
  
}