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, 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<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 M[N][N], color[N], d[N], f[N], nt[N];
int tt,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] = BLACK;
	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; 
	}
	tt = 0; 
	
	for(int j = 0; j < n; j++) {
		if(color[j] == WHITE) {
			dfs_visit(j);
		}
	}
	
	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;
      }	
	}
	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 <ios>
#include <vector>
using namespace std;

void read_data(int n, vector<vector<int>> & Es){
    int u = 0, k = 0, v = 0;
    while (n--){
        cin >> u;
        cin >> k;
        while (k--){
            cin >> v;
            Es[u - 1].push_back(v - 1);
        }
    }
}

void display_result(int n, vector<int> & d, vector<int> & f)

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

void dfs(int node, int & time, vector<vector<int>> & Es, vector<int> & d, vector<int> & f ){
    if (d[node]) return;
    d[node] = time;
    ++time;
    for (auto next_node : Es[node]){
        dfs(next_node, time, Es, d, f);
    }
    f[node] = time;
    ++time;
}

int main()
{
    ios::sync_with_stdio(false);
    int n = 0;
    cin >> n;
    vector< vector<int> > Es(n);
    vector<int> d(n, 0);
    vector<int> f(n, 0);
    read_data(n, Es);
    int time = 1;
    for (int node = 0; node != n; ++node) dfs(node, time, Es, d, f);
    display_result(n, d, f);
    
    return 0;
}

C++: #include <queue>
#include <map>
#include <cstdio>
#include <algorithm>
using namespace std;
map<int,vector<int> >a;
map<int,int>m;
vector<pair<int,pair<int,int> > >v;
int T;
void D(int k){
	m[k]=1;
	int t=T;
	for(int i=0;i<a[k].size();i++)if(!m[a[k][i]])++T,D(a[k][i]);
	T++;
	v.push_back(make_pair(k,make_pair(t,T)));
}
main(){
	int i,j,k,N,n=0;
	for(scanf("%d",&N);n<N;n++)for(scanf("%d%d",&i,&k);k--;a[i].push_back(j))scanf("%d",&j);
	for(T=0,i=1;i<=N;i++)if(!m[i])++T,D(i);
	sort(v.begin(),v.end());
	for(i=0;i<v.size();i++)printf("%d %d %d\n",v[i].first,v[i].second.first,v[i].second.second);
}

C++: #include<bits/stdc++.h>
using namespace std;
int a[101][101],f[101],e[101],nt[101],cur,i,j,n,t=0;
int color[101];
void dfs(int u){
    f[u]=++t;
    color[u]=1;
    for(int v=0;v<n;++v){
        if(color[v]==0&&a[u][v]){
            dfs(v);
        }
    }
    e[u]=++t;
}
int main(){
    int u,v;
    scanf("%d",&n);
    for(i=0;i<n;++i){
        scanf("%d %d",&u,&cur);
        for(j=0;j<cur;++j){
            scanf("%d",&v);
            a[u-1][v-1]=1;
        }
    }
    for(i=0;i<n;++i){
        if(!color[i]){
            dfs(i);
        }
    }
    for(i=0;i<n;++i)    printf("%d %d %d\n",i+1,f[i],e[i]);
    return 0;
}