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 <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <math.h>
#include <complex>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <unordered_map>
#include <set>
#include <bitset>
#include <functional>
#include <assert.h>
using ll=long long;
#define int ll
#define rng(i,a,b) for(int i=int(a);i<int(b);i++)
#define rep(i,b) rng(i,0,b)
#define gnr(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define per(i,b) gnr(i,0,b)
#define eb emplace_back
#define all(x) x.begin(),x.end()
#define SZ(x) ((int)x.size())
#define fi first
#define se second
const int INF = 1e15;
using namespace std;

template<class T> using vc=vector<T>;
template<class T> using vvc=vc<vc<T>>;

using pi=pair<int,int>;
using vi=vc<int>;

template<class T>
inline bool chmax(T &a,T b){if(a<b){a=b;return true;}return false;}
template<class T>
inline bool chmin(T &a,T b){if(a>b){a=b;return true;}return false;}

vi G[200];
int cnt=1;
int s[200],f[200];
void dfs(int v){
    s[v]=cnt++;
    rep(k,SZ(G[v])){
        if(s[G[v][k]]) continue;
        dfs(G[v][k]);
    }
    f[v]=cnt++;
}
signed main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout<<fixed<<setprecision(20);

    int N; cin >> N;
    rep(i,N){
        int a,n; cin >> a >> n;
        a--;
        rep(j,n){
            int b; cin >> b;
            b--;
            G[a].eb(b);
        }
    }
    rep(i,N){
        if(!s[i]) dfs(i);
    }
    rep(i,N){
        cout << i+1 << " " << s[i] << " " << f[i] << "\n";
    }
}

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

using namespace std;

int n, t;
vector<int> G[101];
int d[101], f[101];
bool used[101];

void dfs(int v) {
	used[v] = true;
	d[v] = ++t;
	for (int i = 0; i < G[v].size(); ++i) {
		int e = G[v][i];
		if (!used[e]) dfs(e);
	}
	f[v] = ++t;
}

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

	for (int i = 1; i <= n; ++i)
		if(!used[i]) dfs(i);

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

	return 0;
}

C++: #include<iostream>
#include<vector>
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;

int t = 1;
int n;
int a[105][105];

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

void visit(int u){
  color[u] = GRAY;
  d[u] = t++;

  for(int i = 0; i < n; i++){
    if(a[u][i] == 0) continue;
    if(color[i] == WHITE) visit(i);
  }

    color[u] = BLACK;
    f[u] = t++;
}

void dfs(){
  for(int i = 0; i < n; i++) color[i] = WHITE;

  for(int i = 0; i < n; i++){
    if(color[i] == WHITE) visit(i);
  }
}

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

  d.resize(n+5);
  f.resize(n+5);
  g.resize(n+5);
  color.resize(n+5);

  for(int i = 0; i < n; i++){
    cin >> u >> k;
    u--;

    for(int j = 0; j < k; j++){
      cin >> v;
      v--;
      a[u][v] = 1;
    }
    
  }

  dfs();

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

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

int next(int u) {
	for (int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
		if (m[u][v] == 1)
			return v;
	}
	return -1;
}

void dfs(int u) {
	for (int i = 0; i < n; i++)
		nt[i] = 0;
	stack<int> s;
	s.push(u);
	color[u] = gray;
	d[u] = ++tt;
	while (!s.empty()) {
		int u = s.top();
		int v = next(u);
		if (v != -1) {
			if (color[v] == white) {
				s.push(v);
				color[v] = gray;
				d[v] = ++tt;
			}
		} else {
			s.pop();
			color[u] = black;
			f[u] = ++tt;
		}
	}
}

void dfs_init() {
	tt = 0;
	for (int i = 0; i < n; i++)
		color[i] = white;
	
	for (int i = 0; i < n; i++) {
		if (color[i] == white)
			dfs(i);
	}
	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 j = 0; j < k; j++) {
			cin >> v;
			v--;
			m[u][v] = 1;
		}
	}
	dfs_init();
	return 0;
}