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++: //
// Created by 李青坪 on 2018/11/2.
//

#include <cstdio>
#define MAXN 101
using namespace std;

int graph[MAXN][MAXN];
int nodeTime[MAXN][2];
int countTime = 0;
int n;

void dfs(int i){
    countTime++;
    nodeTime[i][0] = countTime;
    for (int j = 1; j <= n; ++j) {
        if (graph[i][j] != 0 && nodeTime[j][0] == 0){
            dfs(j);
        }
    }
    countTime++;
    nodeTime[i][1] = countTime;
}

int main(){
    scanf("%d", &n);
    int u, k;
    for (int i = 0; i < n; ++i) {
        scanf("%d %d", &u, &k);
        int node;
        for (int j = 0; j < k; ++j) {
            scanf("%d", &node);
            graph[u][node] = 1;
        }
    }
    dfs(1);
    for (int l = 1; l <= n; ++l) {
        printf("%d %d %d\n", l, nodeTime[l][0], nodeTime[l][1]);
    }
}
/*
6
1 2 2 3
2 2 3 4
3 1 5
4 1 6
5 1 6
6 0
 */

C++: #include<iostream>
#include<cstdio>
#define N 100
#define  GRAY 1
#define BLACK 2
using namespace std;
int n,M[N][N];
int color[N],d[N],f[N],tt;
void dfs_visit(int u)
{
  int v;
  color[u] = GRAY;
  d[u] = ++tt;
  for(v = 0;v<n;v++)
  {  if(M[u][v] == 0)
     continue;
  if(color[v] == 0)
    {
      dfs_visit(v);
    }
}
  color[u] = BLACK;
  f[u] == ++tt;
}
void dfs()
{
  int u;
  for(u = 0;u<n;u++)
     color[u] = 0;
  tt = 0;
  for(u = 0;u<n;u++)
  {
    if(color[u] == 0) dfs_visit(u);
  }
  for(u = 0;u<n;u++)
  {
    printf("%d %d %d\n",u+1,d[u],f[u]);
  }
}
int main ()
{
  int u,v,k,i,j;
  scanf("%d",&n);
  for( i = 0;i<n;i++)
    for( j = 0;j<n;j++)
        M[i][j] = 0;
  for( i =0;i<n;i++)
   {
     scanf("%d %d",&n,&k);
     u--;
     for( j = 0;j<n;j++)
       {
         scanf("%d",&v);
         v--;
         M[u][v] = 1;
       }
   }
   dfs();
  return  0 ;
}

C++: #include<stdio.h>
#include<algorithm>
#include<stack>
#include<string.h>
using namespace std;
#define INFTY 2000000001
#define MAX 101
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n = 0;
int adl[MAX][MAX], deg[MAX];
int adm[MAX][MAX];
int color[MAX];
int d[MAX][2];
stack<int> depth;


void dfs() {
  int time = 1;
  for ( int i = 0; i < n; i++ ) {
    color[i] = WHITE;
  }
  depth.push(0);
  color[0] = GRAY;
  d[0][0] = time++;

  while (!depth.empty()) {
    int top = depth.top();

    int next;
    for (int i = 0; i < n; i++) {
      next = i;
      if (adm[top][i] == 1 && color[i] == WHITE) {
        depth.push(i);
        d[i][0] = time++;

        color[i] = GRAY;
        break;
      }
      next = n;
    }

    if (next == n) {
      color[top] = BLACK;
      d[top][1] = time++;
      depth.pop();
    }

    if (depth.empty()) {
      for (int i = 0; i < n; i++) {
        if (color[i] == WHITE) {
          depth.push(i);
          color[i] = GRAY;
          d[i][0] = time++;
        }
      }
    }
  }
}

int main() {
  scanf("%d", &n);
  for ( int i = 0; i < n; i++ ) {
    for ( int j = 0; j < n; j++ ) {
      adm[i][j] = 0;
    }
  }
  for ( int i = 0; i < n; i++ ) {
    int num;
    scanf("%d", &num);
    num--;
    scanf("%d", &deg[num]);
    for ( int j = 0; j < deg[num]; j++) {
      scanf("%d", &adl[num][j]);
      adl[num][j]--;
      adm[num][adl[num][j]] = 1;
    }
  }

  dfs();

  for ( int i = 0; i < n; i++ ) {
    printf("%d %d %d\n", i+1, d[i][0], d[i][1]);
  }



  return 0;
}

C++: #include <cstdio>
#include <vector>
#include <algorithm>

#define rep(i, n) for(int i = 0; i < (n); ++i)

using namespace std;

int n;
vector<int> g[100];
int t;
int p[100];
int q[100];

void dfs(int i){
	p[i] = t++;
	rep(j, g[i].size()){
		int v = g[i][j];
		if(!p[v]){
			dfs(v);
		}
	}
	q[i] = t++;
}

int main(){
	scanf("%d", &n);
	rep(i, n){
		int u, k;
		scanf("%d%d", &u, &k);
		rep(j, k){
			int v;
			scanf("%d", &v);
			g[u - 1].push_back(v - 1);
		}
	}
	rep(i, n){
		if(!p[i]){
			t = 1;
			dfs(i);
		}
	}
	rep(i, n){
		printf("%d %d %d\n", i + 1, p[i], q[i]);
	}
	return 0;
}