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 <iostream>
using namespace std;

void search(int i,int *table, int n, int *d, int *f, int *cnt){
	
	++(*cnt);
	d[i] = *cnt;
	
	for(int j=0;j<n;++j){
		if(table[i*n+j]){
			for(int k=0;k<n;++k){
				table[k*n+j] = 0;
			}
			search(j,table,n,d,f,cnt);
		}
	}
	
	++(*cnt);
	f[i] = *cnt;
}

int main() {
	int n,*table,*d,*f, cnt;
	
	cin>>n;
	table = new int[n*n];
	d = new int[n];
	f = new int[n];
	
	for(int i=0;i<n;++i){
		int u,k,v;
		cin>>u>>k;
		for(int j=0;j<k;++j){
			cin>>v;
			table[(u-1)*n+v-1]=1;
		}
	}
	cnt = 0;
	
	while(true){
		int rest = 0;
		for(int i=0;i<n;++i){
			for(int j=0;j<n;++j){
				if(table[i*n+j]){
					rest = 1;
					break;
				}
			}
			if(rest){
				search(i,table,n,d,f,&cnt);
				break;
			}
		}
		if(!rest){
			break;
		}
	}
	
	for(int i=0;i<n;++i){
		cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
	}
	
	return 0;
}

C++: #include <cstdio>
using namespace std;
int tim = 0;
bool vis[107];
int G[107][107], d[107], f[107];
void dfs(int cur) {
	vis[cur] = true;
	d[cur] = ++tim;
	for (int i = 0; G[cur][i]; i++) {
		if (!vis[G[cur][i]]) dfs(G[cur][i]);
	}
	f[cur] = ++tim;
}
int main() {
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
    	int u, k;
    	scanf("%d%d", &u, &k);
    	for (int j = 0; j < k; j++) {
    		scanf("%d", &G[u][j]);
		}
	}
	for (int i = 1; i <= n; i++) {
		if (!vis[i]) dfs(i);
	}
	for (int i = 1; i <= n; i++) {
		printf("%d %d %d\n", i, d[i], f[i]);
	}
    return 0;
}

C++: #include<stdio.h>
#define N 100
#define WHITE 0
#define GREY 1
#define BLACK 2

int n, M[N][N];
int color[N], d[N], f[N], time;

void dfs_visit(int u)
{
	int v;
	color[u] = GREY;
	d[u] = ++time;
	for(v = 0; v < n; v++)
	{
		if(M[u][v] == 0)
			continue;
		if(color[v] == WHITE)
			dfs_visit(v);
	}
	color[u] = BLACK;
	f[u] = ++time;
}

void dfs()
{
	int u;
	for(u = 0; u < n; u++)
		color[u] = WHITE;
	time = 0;
	
	for(u = 0; u < n; u++)
	{
		if(color[u] == WHITE)
			dfs_visit(u);
	}
	for(u = 0; u < n; u++)
	{
		printf("%d %d %d\n", u + 1, d[u], f[u]);
	}
}

int main()
{
	scanf("%d", &n);
	for(int i = 0; i < n; i++)
		for(int j = 0; j < n; j++)
			M[i][j] = 0;
	int u, k, v;
	for(int i = 0; i < n; i++)
	{
		scanf("%d%d", &u, &k);
		u--;
		for(int j = 0; j < k; j++)
		{
			scanf("%d", &v);
			v--;
			M[u][v] = 1;
		}
	}
	
	dfs();
}

C++: #include <iostream>
#include <vector>
#include <stack>
#include <cstring>
#define N 101

using namespace std;

int visited[N], nt[N], discovery[N], finish[N], tt, n;
vector<int> G[N];

int next(int u) {
    for (int v = nt[u]; v < G[u].size(); v++) {
        nt[u] = v + 1;
        return G[u][v];
    }
    return -1;
}

void dfs(int r) {
    memset(nt, 0, sizeof(nt));

    stack<int> S;
    S.push(r);

    visited[r] = 1;
    discovery[r] = ++tt;

    while (!S.empty()) {
        int u = S.top();
        int v = next(u);

        if (v != -1) {
            if (visited[v] == 0) {
                visited[v] = 1;
                discovery[v] = ++tt;
                S.push(v);
            }
        }
        else {
            S.pop();
            visited[u] = 1;
            finish[u] = ++tt;
        }
    }
}

int main() {
    int u, k, v;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            cin >> v;
            v--;
            G[u].push_back(v);
        }
    }

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

    for (int i = 0; i < n; i++) {
        if (visited[i] == 0) {
            dfs(i);
        }
    }

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

    return 0;
}

C++: #include <iostream>
#include <stack>

using namespace std;

#define MAX 110
int num;
int matrix[MAX][MAX];
int dst[MAX];
int counter = 0;
int D[MAX];
int F[MAX];

void input(){
    cin >> num;
    for(int i=0;i<MAX;i++){
        dst[i] = -1;
        for(int j=0;j<MAX;j++){
            matrix[i][j] = 0;
        }
    }
    for(int i=1;i<=num;i++){
        int v; cin >> v;
        int tmp; cin >>tmp;
        for(int j=0;j<tmp;j++){
            int vi; cin >> vi;
            matrix[v-1][vi-1] = 1;
        }
    }
}

void dfs(int cur){
    counter++;
    D[cur] = counter;
    for(int i=0; i< num;i++){
        if(matrix[cur][i] == 1 && D[i]== 0)
            dfs(i);
    }
    counter++;
    F[cur] = counter;
    return;
}

int main(){
    input();
    for(int i=0;i<MAX;i++){
        D[i] = 0;
        F[i] = 0;
    }
    dfs(0);
    for(int i=0;i<num;i++){
        cout << i+1 << " " << D[i] << " " << F[i] << endl;
    }
}

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

using namespace std;

std::vector<int> graph[100];
int d[100]={0},f[100]={0};
int t = 0;

void dfs(int v){
  t++;
  d[v] = t;
  for(const auto &next_v:graph[v]){
    if(d[next_v]==0){
      dfs(next_v);
    }
  }
  t++;
  f[v] = t;
}

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