Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

C++: #include <bits/stdc++.h>
#define REP(i,n) for (int i = 0; i <(n); ++i)
#define ALL(v) v.begin(), v.end()
using namespace std;
//using ll = long long;
//using P = pair<int,int>;
//static const double PI = acos(-1);


//---------------------------//
//DFS 再帰関数を利用


static const int N     = 100;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;

//隣接行列
int n, M[N][N];
int color[N], d[N], f[N], tt;

void dfs_visit(int u){
  //cout << "u: " << u << endl; //来訪地点のチェック
  color[u] = GRAY;
  d[u] = ++tt;  //最初に訪れたときの処理
  REP(v,n){
    if(M[u][v] == 0) continue;
    //cout << "v: " << v << endl; // 次に向かう点をチェック
    if(color[v] == WHITE) {
      dfs_visit(v); //再帰
    }
  }
  color[u] = BLACK;
  f[u] = ++tt;  //最後に訪れたときの処理

}


void dfs(){
  //int u;
  // 初期化
  REP(u,n) color[u] = WHITE;
  tt = 0;
  //
  REP(u,n) {
    if( color[u] == WHITE) dfs_visit(u); //再帰関数に
  }
  REP(u,n){
    cout << u+1 << " " << d[u] << " " << f[u] << endl;
    //cout << color[u] << endl;
  }


}


int main(){
  int u,k,v;
  cin >> n;
  //隣接行列の初期化
  REP(i,n) REP(j,n) M[i][j] = 0;


  //隣接行列の作製
  REP(i,n){
    cin >> u >> k;
    --u;
    REP(j,k){
      cin >> v;
      --v;
      M[u][v] = 1;
    }

  }
  //dfs
  dfs();


  //隣接行列のoutput(確認用)
  //REP(i,n) {REP(j,n) cout << M[i][j];cout << endl;}



  return 0;
}

C++: #include<iostream>
#include<stack>
const int N = 100;
using namespace std;
int n,M[N][N];
int color[N],nt[N],d[N],f[N],start;
int next(int u){
	for(int i=nt[u];i<n;i++){
        nt[u] = i+ 1;
        if(M[u][i]) return i;
    }
	return -1;
}
void dfs_visit(int u){
    for(int i=0;i<n;i++) nt[i] = 0;
    stack<int> s;
	s.push(u);
	color[u] = 1;
	d[u] = ++start;
	while(!s.empty()){
		int x = s.top();
		int v = next(x);
		if(v!=-1){
			if(!color[v]){
				s.push(v);
				d[v] = ++start;
				color[v] = 1;
			}
		}else{
			s.pop();
            color[x] = 1;
			f[x] = ++start;
		}
	}
}
void dfs(){
	start = 0;
	for(int i=0;i<n;i++)
            if(!color[i])
	            dfs_visit(i);
	for(int i=0;i<n;i++)
		printf("%d %d %d\n",i+1,d[i],f[i]);
}
int main(){
	scanf("%d",&n);
	for(int i=0;i<n;i++){
		int u,k,v;
		scanf("%d%d",&u,&k);
		while(k--){
			scanf("%d",&v);
			M[u-1][v-1] = 1;
		}
	}
	dfs();
	return 0;
}

C++: #include <stdio.h>
#define REP(i,n) for(int i=0;i<n;i++)
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
int n,M[N][N]={0};
int color[N]={WHITE},D[N],F[N],tt=0;
void DFS_VISIT(int u){
  int v;
  color[u]=GRAY;
  D[u]=++tt;
  REP(v,n){
    if(M[u][v]==0) continue;
    if(color[v]==WHITE) DFS_VISIT(v);
  }
  color[u]=BLACK;
  F[u]=++tt;
}
void DFS(){
  int u;
  REP(u,n) if(color[u]==WHITE) DFS_VISIT(u);
  REP(u,n) printf("%d %d %d\n",u+1,D[u],F[u]);
}
int main(){
  int u,v,k;
  scanf("%d",&n);
  REP(i,n){
    scanf("%d %d",&u,&k);
    u--;
    REP(j,k){
      scanf("%d",&v);
      M[u][--v]=1;
    }
  }
  DFS();
  return 0;
}

C++: #include <iostream>
//#include <iomanip>
//#include <string>
#include <vector>
#include <algorithm>
//#include <utility>
//#include <set>
//#include <map>
//#include <queue>
//#include <deque>
//#include <bitset>
//#include <math.h>
using namespace std ;
using ll = long long ;
//using ld = long double ;
using vll = vector<ll> ;
using vvll = vector<vll> ;
//using vc = vector<char> ;
//using vvc = vector<vc> ;
//using vb = vector<bool> ;
//using vvb = vector<vb> ;
//using pll = pair<ll,ll> ;
#define all(v) v.begin(),v.end()
//ll mod = 1000000007 ;
//long double pie = acos(-1) ;
//ll INF = 1000000000000 ;

//void yorn(bool a){if(a) cout << "Yes" << endl ; else cout << "No" << endl ;}
//void YorN(bool a){if(a) cout << "YES" << endl ; else cout << "NO" << endl ;}
//ll gcd(long long a,long long b){if(b==0) return a ; return gcd(b,a%b) ;}
//ll lcm(long long a,long long b){return a/gcd(a,b)*b ;}
//ll sa(long long a,long long b){if(a>b) return a-b ; return b-a ;}
//void fix_cout(){cout << fixed << setprecision(20) ;}
//void chmin(ll &a,ll b){if(a>b) a = b ;}

ll cnt = 1 ;

void DFS(vvll &g,vvll &ans,ll p){
	if(ans.at(p).at(0)!=-1) return ;
	ans.at(p).at(0) = cnt ;
	cnt++ ;
	for(int i=0;i<g.at(p).size();i++){
		DFS(g,ans,g.at(p).at(i)) ;
	}
	ans.at(p).at(1) = cnt ;
	cnt++ ;
}

int main(){
	ll n ; cin >> n ;
	vvll g(n,vll(0)) ;
	for(int i=0;i<n;i++){
		ll a,b ;
		cin >> a >> b ;
		vll c(b) ;
		for(int j=0;j<b;j++) cin >> c.at(j) ;
		sort(all(c)) ;
		for(int j=0;j<b;j++) g.at(i).emplace_back(c.at(j)-1) ;
	}
	vvll ans(n,vll(2,-1)) ;
	for(int i=0;i<n;i++){
		if(ans.at(i).at(0)==-1) DFS(g,ans,i) ;
	}
	for(int i=0;i<n;i++) cout << i+1 << " " << ans.at(i).at(0) << " " << ans.at(i).at(1) << "\n" ;
}

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

vector<int> G[100];
pair<int, int> T[100];
const int Inf = 10000*100000+100;
int timer = 1;

int main() {
  void dfs(int cur);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++)
  {
    int u, k;
    cin >> u >> k;
    for (int l = 0; l < k; l++) {
      int v;
      cin >> v;
      G[i].push_back(v - 1);
    }
    T[i] = make_pair(Inf, Inf);
  }
  for (int i = 0; i < n; i++) {
    if (T[i].first == Inf) {
      dfs(i);
    }
  }
  for (int i = 0; i < n; i++)
  {
    cout << i + 1 << " " << T[i].first << " " << T[i].second << endl;
  }
}

void dfs(int cur) { // cur を訪問
  // cur の訪問時刻を記録
  T[cur].first = timer;
  timer += 1;
  // 動作確認用表示
  for (int dst : G[cur]) { // 全ての節点 dst について
    if (T[dst].first == Inf)
    { // cur から dst に辺があり，dst を未訪問なら
      dfs(dst);
    }
  }
  T[cur].second = timer;
  timer += 1;
}