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<bits/stdc++.h>
#define N 105
using namespace std;
int n,u,k,v,e[N][N],cnt;
int ans1[N],ans2[N];
bool used[N];
 
void dfs(int x){
  if(used[x])return;
  used[x]=true;
  ans1[x]=cnt++;
  for(int i=0;i<n;i++)
    if(e[x][i])dfs(i);
  ans2[x]=cnt++;
}
 
int main(){
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v;
      e[u-1][v-1]=1;
    }
  }
  cnt=1;
  for(int i=0;i<n;i++)
    if(!used[i])dfs(i);
  
  for(int i=0;i<n;i++)
    cout<<i+1<<' '<<ans1[i]<<' '<<ans2[i]<<endl;

  return 0;
}

C++: #include <stdio.h>
#define  MAX 100
#define FIRST 0
#define MIDDLE 1
#define END 2

int n,M[MAX][MAX];
int point[MAX],d[MAX],f[MAX],t;

void dfs_visit(int u){
    int v;
    point[u]=MIDDLE;
    d[u]=++t;
    for(v=0;v<n;v++){
        if(M[u][v]==0)continue;
        if(point[v]==FIRST){
            dfs_visit(v);
        }
    }
    point[u]=END;
    f[u]=++t;
}
void dfs(){
    int u;

    for(u=0;u<n;u++)point[u]=FIRST;
    t=0;

    for(u=0;u<n;u++){
        if(point[u]==FIRST)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",&u,&k);
        u--;
        for(j=0;j<k;j++){
            scanf("%d",&v);
            v--;
            M[u][v]=1;
        }
    }
    dfs();
    
    return 0;
}

C++: #include <bits/stdc++.h>
#define FOR(I,X,Y) for(long int I=X;I<Y;I++)
#define REP(I,X) for(long int I=X;I>=0;I--)
#define INF 1000000007
using namespace std;

int Adj[101][101];
int d[101],f[101];

int main(){
  int n,u,k,v,t=1;
  cin >> n;
  FOR(i,0,n){
    cin >> u >> k;
    FOR(j,0,k){
      cin >> v;
      Adj[u][v] = 1;
    }
  }
  stack<int> s;
  while(1){
    bool flag2 = 1;
    FOR(i,1,n+1){
      if(d[i] == 0){
        s.push(i);
        flag2 = 0;
        break;
      }
    }
    if(flag2)break;
    while(s.size()){
      if(!d[s.top()])d[s.top()] = t;
      bool flag = 0;
      FOR(i,1,n+1)if(Adj[s.top()][i] && !d[i]){
        s.push(i);
        FOR(j,1,n+1)Adj[j][i] = 0;
        flag = 1;
        break;
      }
      t++;
      if(!flag){
        f[s.top()] = t;
        s.pop();
      }
    }
    t++;
  }
  FOR(i,1,n+1)cout << i << " " << d[i] << " " << f[i] << endl;
}