Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

C++: #include<iostream>
#include<stack>
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, tt;
int M[N][N], color[N], d[N], f[N], nt[N]; 

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;
		for(v = 0; v < n; v++) {
			if(M[u][v] == 0) continue;
			if(color[v] != WHITE) continue;
			break; 
		}
		if(v != n) {
			if(color[v] == WHITE) {
			   color[v] = GRAY;
			   d[v] = ++tt;
			   S.push(v); 	
		    }
		} 
		for(v = 0; v < n; v++) {
			if(M[u][v] == 1) break;
		}
		if(v == n){
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


void dfs() {
	for(int i = 0; i < n; i++) {
	     color[i] = WHITE;
	}
	tt = 0;
		
	for(int u = 0; u < n; u++) {
		if(color[u]) dfs_visit(u);
	}

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

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

C++: #include <iostream>
#include <utility>
#define N 	100

using namespace std;

int T[N+1][N+1];
pair<int , int> M[N+1];
int t = 0;

void init(){
	for (int i = 0; i < 100; ++i)
	{
		M[i].first = 0;
		M[i].second = 0;
		for (int j = 0; j < 100; ++j)
		{
			T[i][j] = 0;
		}
	}
}

void DispTable(int n){
	for (int i = 1; i <= n; ++i)
	{
		for (int j = 1; j <= n; ++j)
		{
			cout << T[i][j];
			if(j!=n) cout << " ";
		}
		cout << endl;
	}
}

void DispM(int n){
	for (int i = 1; i<=n; i++)
	{
		cout << i << " " << M[i].first << " " << M[i].second << endl;
	}
}

void dfs(int cur,int n){
	t++;
	M[cur].first = t;
	// cerr << "visiting " << cur << " " << t << endl;

	for (int i = 1; i <= n; ++i)
	{
		if(i != cur && T[cur][i] == 1 && M[i].first == 0) dfs(i,n);
	}
	t++;
	M[cur].second = t;
}

int main(){
	int n;
	cin >> n;
	init();
	for (int i = 0; i < n; ++i)
	{
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			int v;
			cin >> v;
			T[u][v] = 1;	
		}
	}
	// DispTable(n);
	dfs(1,n);
	DispM(n);
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

// macro
#define rep(i,n) for(i=0;i<n;i++)
#define ll long long
#define all(v) v.begin(), v.end()

// code starts
int times=1;

void dfs(int now,vector<int> &fvisit,vector<int> &fin, vector<vector<int>> &vs)
{
  if(fvisit[now]==-1)
  {
    fvisit[now]=times;
    times++;
  }
  else return;
  int i;
  rep(i,vs[now].size())
  {
    if(fvisit[vs[now][i]]==-1)
    {
      dfs(vs[now][i],fvisit,fin,vs);
    }
  }
  fin[now]=times;
  times++;
}

int main()
{
  int n;cin>>n;
  vector<vector<int>> vs(n);
  int i,j;
  rep(i,n)
  {
    int u,k;cin>>u>>k;
    u--;
    rep(j,k)
    {
      int vj;cin>>vj;
      vj--;
      vs[u].emplace_back(vj);
    }
  }
  vector<int> fvisit(n,-1);
  vector<int> fin(n,-1);
  rep(i,n)
  {
    dfs(i,fvisit,fin,vs);
  }
  rep(i,n)
  {
    cout<<i+1<<' '<<fvisit[i]<<' '<<fin[i]<<endl;
  }
}

C++: #include<stdio.h>
#define N 100
#define WHITE 0
#define GRAY 1 
#define BLACK 2
 
int n, M[N][N];
int color[N], d[N], f[N], tt; 

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

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

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;

#define rep(i, n) for (int i = 0; i < n; ++i)
#pragma region Debug
template <typename T>
void view(const std::vector<T> &v)
{
    for (const auto &e : v)
    {
        std::cout << e << " ";
    }
    std::cout << std::endl;
}
template <typename T>
void view(const std::vector<std::vector<T>> &vv)
{
    for (const auto &v : vv)
    {
        view(v);
    }
}
#pragma endregion

vector<vector<int>> g;
vector<int> d, f;

int dfs(int v, int t)
{
    // cout << v << " ";
    if (f[v] != INT32_MAX)
    {
        return f[v];
    }
    if (d[v] != INT32_MAX && f[v] == INT32_MAX)
    {
        return t - 1;
    }

    d[v] = min(d[v], t);

    int tt = t + 1;
    for (auto to : g[v])
    {
        if (v == to)
            continue;
        tt = max(tt, dfs(to, tt) + 1);
    }
    f[v] = min(tt, f[v]);

    return tt;
}

int main()
{
    int n;
    cin >> n;
    g = vector<vector<int>>(n, vector<int>());
    d = vector<int>(n, INT32_MAX);
    f = vector<int>(n, INT32_MAX);

    rep(i, n)
    {
        int k;
        cin >> k >> k;
        rep(j, k)
        {
            int t;
            cin >> t;
            t--;
            g[i].emplace_back(t);
        }
    }

    int t = 1;
    rep(i, n)
    {
        if (f[i] == INT32_MAX)
        {
            t = dfs(i, t) + 1;
        }
    }

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

    return 0;
}

C++: #include<stdio.h>

int d[100],f[100],n,g[100][100],time=1;

int func(int m){
    d[m]=time++;
    int i,j;
    for(i=0;i<n;i++){
        if(g[m][i]==1 && d[i]==0){
            func(i);
        }
    }
    f[m]=time++;
}

int main(void){
    int i, j, u, k, v;
    scanf("%d",&n);
    for(i=0;i<n;i++){
        scanf("%d %d",&u,&k);
        for(j=0;j<k;j++){
            scanf("%d",&v);
            g[u-1][v-1]=1;
        }
    }
    func(0);
    for(i=0;i<n;i++){
        if(d[i]==0){
            func(i);
        }
    }
    for(i=0;i<n;i++){
        printf("%d %d %d\n",i+1,d[i],f[i]);
    }
    return 0;
}