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++: #include <iostream>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <algorithm>

typedef long long ll;

using namespace std;

int t = 0;
vector<vector<int> > a;
vector<int> d, f;
vector<bool> v;

void dfs(int i) {
  v[i] = true;
  d[i] = ++t;
  for (int j : a[i]) {
    if (!v[j]) {
      dfs(j);
    }
  }
  f[i] = ++t;
}

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

    }
    v.resize(n, false);
    d.resize(n);
    f.resize(n);

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

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

C++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <stdio.h>
#include <list>
#define black 0
#define red 1
#define white -1
#define maxn 110
using namespace std;

int tot = 0;
int book[maxn] = {}, t[maxn][2] = {};
list<int> map[maxn];

void dfs(int u)
{
	book[u] = red;
			t[u][0] = ++tot;
			for (list<int>::iterator it = map[u].begin(); it != map[u].end(); it++)
			{
				if (book[*it - 1] == black)
				{
					dfs(*it - 1);
				}
			}
			book[u] = white;
			t[u][1] = ++tot;
	return;
}
int main()
{
	int n;
	scanf("%d", &n);
	for (int i = 0; i < n; i++)
	{
		int u, k, v;
		scanf("%d%d", &u, &k);
		u--;
		for (int i = 0; i < k; i++)
		{
			scanf("%d", &v);
			map[u].push_back(v);
		}
	}
	for (int i = 0; i < n; i++)
		if (book[i] == black)
			dfs(i);
	for (int i = 0; i < n; i++)
	{
		printf("%d %d %d\n", i + 1, t[i][0], t[i][1]);;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for(int i = 0; i < n; i++)
#define REPR(i, n) for(int i = n - 1; i >= 0; i--)
#define FOR(i, m, n) for(int i = m; i < n; i++)
#define FORR(i,m,n) for(int i = m - 1; i >= n; i--)
#define ALL(v) v.begin(), v.end()
#define CMAX(m, x)  m = max(m,x)
#define CMIN(m, x)  m = min(m,x)
#define itn int
#define Yes() cout << "Yes" << endl
#define No() cout << "No" << endl
#define YES() cout << "YES" << endl
#define NO() cout << "NO" << endl
typedef long long lint;
typedef long double ldouble;
const int INF = 1e9;
const lint LINF = 1e18;

int cnt = 0;
void dfs(int i,vector<vector<int>> &g, vector<vector<int>> &ans){
    if(ans[i][0] == 0){
        cnt++; 
        ans[i][0] = cnt;
        REP(j,g[i].size()){
            dfs(g[i][j] - 1,g,ans);  
        }
        cnt++;

        ans[i][1] = cnt;
    }
}
int main(){
    int n;
    cin >> n;
    int u,k;
    vector<vector<int>> g(n);
    vector<vector<int>> ans(n,vector<int>(2,0));
    REP(i,n){
        cin >> u >> k;
        g[u - 1] = vector<int>(k);
        REP(j,k)
            cin >> g[u - 1][j];
    }
    REP(i,n)
        dfs(i,g,ans);
    REP(i,n){
        printf("%d %d %d\n",i + 1, ans[i][0],ans[i][1]);
    }

    return 0;
}

C++: #include <iostream>
#include <string>
#include <map>
#include <stack>
#include <algorithm>
using namespace std;
#define MAX 100000

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];

int next(int u){
  for(int v=nt[u];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;

  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 <stdio.h>

int A[101][101];
int ans[101][3];
int an = 1;


int judge(int i, int j){
  if(ans[i][j] == 0){
    ans[i][j] = an;
    an++;
  }
}

int serch(int a[101][101], int  ni, int n){
  int  j;
  
  for(j=0; j<n; j++){
    if(A[ni][j] == 1){
      judge(j, 1);
      serch(A, j, n);
    }
  }
  judge(ni, 2);
}

int  main(){
  int i, j, k, n, x, y;
  
  scanf("%d", &n);
  
  for(i=0; i<n; i++){
    for(j=0; j<n; j++)
      A[i][j] = 0;
    ans[i][0] = i+1;
  }
  
  for(i=0; i<n; i++){
    scanf("%d %d", &x, &y);
    for(j=0; j<y; j++){
      scanf("%d", &k);
      A[i][k-1] = 1;
    }
  }
  
  for(j=0; j<n; j++){
  judge(j,1);
    for(i=0; i<n; i++){
      if(A[j][i] == 1){
        judge(i, 1);
        serch(A, i, n);
      }
    }
  judge(j, 2);
  }
  
  for(i=0; i<n; i++){
    for(j=0; j<3; j++){
      if(j>0)
        printf(" ");
      printf("%d", ans[i][j]);
    }
    printf("\n");
  }
  
  return 0;
}