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<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]; 

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_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 {
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


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

C++: #include <iostream>

using namespace std;

int Time=0,d[101],f[101],v[101][101];
void Init()
{
    int i;
    for(i=1;i<=100;i++)
        d[i]=0;
}
void dfs(int cur,int n)
{
    int i;
    Time += 1;
    d[cur]=Time;
    for(i=1;i<=n;i++)
    {
        if(v[cur][i]==1 && d[i]==0)
            dfs(i,n);
    }
    Time += 1;
    f[cur] = Time;
}
int Find(int n,int d[])
{
    int flag=0,i;
    for(i=1;i<=n;i++)
        if(d[i]==0)
        {
            flag=i;
            break;
        }
    return flag;
}
int main()
{
    int n,m,k,i,j,flag;
    cin >> n;
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
            v[i][j]=0;
    for(i=1;i<=n;i++)
    {
        cin >> i >> k;
        for(j=1;j<=k;j++)
        {
            cin >> m;
            v[i][m]=1;
        }
    }
    Init();
    dfs(1,n);
    while(1)
    {
        flag = Find(n,d);
        if(flag == 0)
            break;
        else    dfs(flag,n);
    }
    for(i=1;i<=n;i++)
    {
        cout << i << ' ' << d[i] << ' ' << f[i] << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
 
using ll = long long;
using ld = long double;
#define FOR(i, m, n) for (int i = (m); i < (n); i++)
#define FORR(i, m, n) for (int i = (m); i >= (n); i--)
#define REP(i, n) FOR(i, 0, (n))
#define REPR(i, n) FORR(i, (n) - 1, 0)
#define REP1(i, n) FOR(i, 1, (n) + 1)
#define REPS(c, s) for (char c : s)
#define ALL(c) (c).begin(), (c).end()
#define SORT(c) sort(ALL(c))
#define REV(c) reverse(ALL(c))
#define sz(v) (int)v.size()
#define endl '\n'
template<class T> inline bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template<class T> inline bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
template<class T> inline void printv(vector<T>& v) {int n = sz(v); REP(i, n) cout << v[i] << (i == n - 1 ? endl : ' ');}
const int MOD = 1000000007;
const int INF = 1000000001;
const ll LINF = 1000000001000000001LL;
 
void solve();
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(numeric_limits<double>::max_digits10);
    solve();
    return 0;
}

void solve() {
    int n;
    cin >> n;
    vector<vector<int>> g(n, vector<int>());
    int u, k;
    REP(i, n) {
        cin >> u >> k;
        u--;
        int v;
        REP(j, k) {
            cin >> v;
            v--;
            g[u].emplace_back(v);
        }
    }

    vector<int> d(n, 0);
    vector<int> f(n, 0);
    int count = 0;
    function<void(int)> dfs = [&](int c) {
        if (d[c] == 0) d[c] = count;
        for (auto t : g[c]) {
            if (d[t] != 0) continue;
            count++;
            dfs(t);
        }
        count++;
        f[c] = count;
    };
    REP(i, n) if (d[i] == 0) {
        count++;
        dfs(i);
    }

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

C++: #include <iostream>
#include <vector>
#include <stack>
#include <utility>
using namespace std;
int _time = 0;
stack<int> route;
void dfs(int root, vector<vector<bool>> &conn_mat, vector<bool> &accessed, vector<pair<int, int>> &result)
{
	accessed[root] = true;
	result[root].first = _time;
	int index;
	bool end = true;
	for (index = 0; index < conn_mat.size(); index++)
	{
		if (conn_mat[root][index] == true && accessed[index] == false)
		{
			_time++;
			result[index].first = _time;
			dfs(index, conn_mat, accessed, result);
			end = false;
		}
	}
	if (end)
	{
		_time++;
		result[root].second = _time;
		return;
	}
	_time++;
	result[root].second = _time;
	return;
}

int main()
{

	int n_node, index, n_cn, cn;
	cin >> n_node;
	vector<bool> vertex(n_node, false);
	vector<vector<bool>> conn_mat(n_node, vertex);
	vector<bool> &accessed = vertex;
	vector<pair<int, int>> result(n_node, make_pair(1, 0));
	while (n_node--)
	{
		cin >> index >> n_cn;
		while (n_cn--)
		{
			cin >> cn;
			conn_mat[index - 1][cn - 1] = true;
		}
	}
	bool end = false;
	while (!end) {
		_time++;
		int i = 0;
		while (accessed[i]) {
			i++;
		}
		dfs(i, conn_mat, accessed, result);
		end = true;
		for (auto acc : accessed) {
			end = end && acc;
		}
	}
	int i = 1;
	for (auto out : result) {
		cout << i << ' ' << out.first << ' ' << out.second << endl;
		i++;
	}
	return 0;
}