Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	ans := make([][2]int, N)
	time := 0
	found := make(map[int]bool)
	var dfs func(cur int)
	dfs = func(cur int) {
		time++
		ans[cur][0] = time
		found[cur] = true
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if !found[next] {
				dfs(G[cur][i])
			}
		}
		time++
		ans[cur][1] = time
	}
	for i := 0; i < N; i++ {
		if !found[i] {
			dfs(i)
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprint(wtr, i+1)
		for j := 0; j < 2; j++ {
			fmt.Fprint(wtr, " ")
			fmt.Fprint(wtr, ans[i][j])
		}
		fmt.Fprintln(wtr)
	}
	wtr.Flush()
}

C++: #include <iostream>
using namespace std;

void dfs(int cur);
int df[100][2]={};
bool dc[100]={};
bool adj[100][100]={};//初期化を忘れない
int n,u,v,k;
int t = 1;

int main(){
  cin >> n;
  for (int i=0; i<n; i++){
    cin >> u >> k;
    for (int j=0; j<k; j++){
      cin >> v;
      adj[u-1][v-1] = true;
    }
  }
  
 
  dfs(0);
  
  for (int i=0; i<n; i++)
    cout << i+1 << " " << df[i][0] << " " << df[i][1] << endl;

}

void dfs(int cur){
  dc[cur] = true;
  df[cur][0] = t;
  t += 1;
  bool a = false;
  for (int i=0; i<n; i++){
    if (adj[cur][i] && !dc[i]){
      dfs(i);
      a = true;
    }
  }
  if (!a) t -= 1;
  t += 1;
  df[cur][1] = t;  
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<stack>
#define white 0
#define grey 1
#define black -1
using namespace std;

int a[110][110],n;
int color[110];
int t;
int ts[110],te[110];
int nt[110];

void dfsinit()
{
    for(int i=1;i<=n;i++)
        {
            color[i]=white;
            nt[i]=1;
        }
}

int next(int i)
{
    for(int j=nt[i];j<=n;j++)
    {
        nt[i]=j+1;
        if(a[i][j]) return j;
    }
    return -1;
}

void dfsvisit(int u)
{
    for(int i=1;i<=n;i++)
        nt[i]=1;
    stack<int>s;
    s.push(u);
    ts[u]=++t;
    color[u]=grey;
    while(!s.empty())
    {
       int r=s.top();
       int v=next(r);
       if(v!=-1)
       {
          if(color[v]==white)
          {
              color[v]=grey;
              ts[v]=++t;
              s.push(v);
          }
       }
       else
       {
           color[r]=black;
           te[r]=++t;
           s.pop();
       }
    }
}

void dfs()
{
    dfsinit();

    for(int i=1;i<=n;i++)
    {
        if(color[i]==white)
        {
            dfsvisit(i);
        }
    }
}

int main()
{
   int key,d,x;
   t=0;
   memset(a,0,sizeof(a));
   scanf("%d",&n);
   for(int i=1;i<=n;i++)
   {
       scanf("%d%d",&key,&d);
       for(int j=1;j<=d;j++)
       {
        scanf("%d",&x);
        a[key][x]=1;
       }
   }

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

C++: #include <iostream>
#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;

int color[MAX];
bool M[MAX][MAX];
int n;
int tt;
int d[MAX];
int f[MAX];

void dfs(int u) {
	color[u] = GRAY;
	d[u] = ++tt;
	for (int v = 0; v < n; v++) {
		if (M[u][v] && color[v] == WHITE) {
			dfs(v);
		}
	}
	color[u] = BLACK;
	f[u] = ++tt;
}

void dfs_init() {
	for (int i = 0; i < n; i++) {
		color[i] = WHITE;
	}
	tt = 0;
	for (int u = 0; u < n; u++) {
		if (color[u] == WHITE) {
			dfs(u);
		}
	}
	for (int u = 0; u < n; u++) {
		cout << u + 1 << " ";
		cout << d[u] << " " << f[u] << endl;
	}
}

int main()
{
	cin >> n;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			M[i][j] = false;
		}
		d[i] = f[i] = 0;
	}
	for (int i = 0; i < n; i++) {
		int u, k, v;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			M[u - 1][v - 1] = true;
		}
	}
	
	dfs_init();

	return 0;
}

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

static const int N = 101;

using namespace std;

vector<vector<int> > V;
int d[N], f[N];
int step = 1;

void dfs (int v) {
  if (d[v])
    return;

  d[v] = step++;

  for (vector<int>::iterator it = V[v].begin(); it != V[v].end(); it++) {
    if (!d[*it]) {
      dfs(*it);
    }
  }

  f[v] = step++;
}

void dfs_init (int n) {
  for (int i = 1; i <= n; i++)
    dfs(i);
}

int main () {
  int n, v, v2, k;
  // stack<int> S;
  // vector<vector<int> > V;

  for (int i = 0; i <= N; i++) {
    vector<int> A;
    V.push_back(A);
  }
  for (int i = 0; i <= N; i++)
    d[i] = f[i] = 0;

  cin >> n;

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

    for (int j = 0; j < k; j++) {
      cin >> v2;
      V[v].push_back(v2);
    }
  }

  // for (int i = 1; i <= n; i++) {
  //   for (int j = 1; j <= n; j++)
  //     cout << V[i][j] << (j == n ? "" : " ");
  //   cout << endl;
  // }

  // int step = 1;
  // bool breaked = false;

  // S.push(1);
  // d[S.top()] = step++;

  // while (S.size()) {
  //   // cout << "S.top = " << S.top() << endl;
  //   breaked = false;

  //   for (vector<int>::iterator it = V[S.top()].begin(); it != V[S.top()].end(); it++) {
  //     if (!d[*it]) {
  //       d[*it] = step++;
  //       S.push(*it);
  //       breaked = true;
  //       break;
  //     }
  //   }

  //   if (!breaked) {
  //     f[S.top()] = step++;
  //     S.pop();

  //     if (S.empty()) {
  //       for (int i = 1; i <= n; i++) {
  //         if (!d[i]) {
  //           S.push(i);
  //           d[i] = step++;
  //           break;
  //         }
  //       }
  //     }
  //   }
  // }

  dfs_init(n);

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

  return 0;
}