Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	resolve(parseProblem())
}

type graph struct {
	size  int
	edges [][]int
}

func parseProblem() *graph {
	n := scanInt(sc)
	g := &graph{
		size:  n,
		edges: make([][]int, n),
	}
	for i := 0; i < g.size; i++ {
		_ = scanInt(sc)
		k := scanInt(sc)
		g.edges[i] = make([]int, k)
		for j := 0; j < k; j++ {
			g.edges[i][j] = scanInt(sc) - 1
		}
	}
	return g
}

func resolve(g *graph) {
	ds := make([]int, g.size)
	fs := make([]int, g.size)
	time := 0
	for i := 0; i < len(ds); i++ {
		if ds[i] == 0 {
			time++
			time = _dfs(ds, fs, time, g, i)
		}
	}
	for i := 0; i < len(ds); i++ {
		fmt.Println(i+1, ds[i], fs[i])
	}
	return
}

func _dfs(ds, fs []int, time int, g *graph, idx int) int {
	ds[idx] = time
	for _, next := range g.edges[idx] {
		if ds[next] > 0 {
			continue
		}
		time++
		time = _dfs(ds, fs, time, g, next)
	}
	time++
	fs[idx] = time
	return time
}

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include<iostream>
const int MAXN = 105;
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
int a[MAXN][MAXN];
int color[MAXN];
int d[MAXN];
int f[MAXN];
int n, tt = 0;
using namespace std;

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

void dfs_init()
{
	int u;
	for(u = 0; u < n; u++)
		color[u] = WHITE;
	
	for(u = 0; u < n; u++)
	{
		if(color[u] == WHITE)
			dfs(u);
	}
	
	for(u = 0; u < n; u++)
	{
		cout << u+1 << " " << d[u] << " " << f[u] << endl;	
	}	
} 

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

C++: #define _CRT_SECURE_NO_WARNINGS

#include<iostream>
#include<functional>
#include<algorithm>
#include<stack>
#include<queue>
#include<iomanip>
#include<set>
#include<map>
#include<utility>
#include<string>
#include<vector>

using namespace std;

#define LL long long
const int dx[4] = { 1,-1,0,0 };
const int dy[4] = { 0,0,1,-1 };
bool OOA(int x,int y,int H,int W){return (0<=x&&x<H)&&(0<=y&&y<W);}

struct Graph{
	int V,E,t;
	vector<int>cost;
	vector<int>d;
	vector<int>f;
	vector<bool>vzt;
	vector<vector<int>>adj;
	void init(int dflt){//dflt!=0
		t=1;
		adj=vector<vector<int>>(V+1);
		cost = vector<int>(V + 1, dflt);
		d = vector<int>(V + 1, dflt);
		f = vector<int>(V + 1, dflt);
		vzt=vector<bool>(V+1,false);
	}

	void bfs(int s, int scost){
		queue<pair<int,int>>q;
		q.push({scost,s});
		vzt[s]=true;
		cost[s]=0;
		while(!q.empty()){
			auto top=q.front();
			q.pop();
			int cst=top.first,now=top.second;
			for(int i=0;i<adj[now].size();i++){
				if(!vzt[adj[now][i]]){
					vzt[adj[now][i]]=true;
					cost[adj[now][i]]=cost[now]+1;
					q.push({cost[adj[now][i]],adj[now][i]});
				}
			}
		}
	}

	void dfs(int now){
		if(d[now]==-1){d[now]=t;t++;}
		else return;
		for(int i=0;i<adj[now].size();i++)dfs(adj[now][i]);
		if(f[now]==-1){f[now]=t;t++;}
		return;
	}
};

int n;
Graph G;

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

C++: #include<iostream>
int s[100]={0},f[100]={0},B[100][100]={0},A[100]={0},d[100],c[100]={0},cnt=1,tmp;
bool con(int A[],int n){
	for(int i=0;i<n;i++){
		if(A[i]==0){
			tmp=i;
			return true;
		}
	}
	return false;
}
void search(int v){
  A[v]=1;
  s[v]=cnt++;
  for(int i=0;i<d[v];i++){
    if(A[B[v][i]]==0){
      search(B[v][i]);
    }
  }
  f[v]=cnt++;
}
int main(){
  int n,num,flag;
  std::cin>>n;
  for(int i=0;i<n;i++){
    std::cin>>num>>d[i];
    for(int j=0;j<d[i];j++){
      std::cin>>flag;
      B[num-1][j]=flag-1;
    }
  }
  search(0);
	while(con(A,n)){
		search(tmp);
	}
  for(int i=0;i<n;i++){
    std::cout<<i+1<<" "<<s[i]<<" "<<f[i]<<"\n";
  }
  return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

#define ll long long
typedef complex<double> P;

int main() {
  int n; cin >> n;
  int adj[n][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;
      adj[u-1][v-1] = 1;
    }
  }

  int d[n] = {};
  int f[n] = {};
  int t = 1;

  stack<int> st;
  st.push(0);

  while (!st.empty()) {
    int v = st.top();

    if(d[v] == 0) {
      d[v] = t;
    }

    for (int i = 0; i < n; i++) {
      if(adj[v][i] == 1 && d[i] == 0) {
        st.push(i);
        break;
      }
    }

    if(st.top() == v) {
      f[v] = t+1;
      st.pop();
    }

    t++;
  }

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

}