Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	timer := 1
	for {
		startNode := findStartNode(childrenMap, timeRecordMap)
		if startNode > 0 {
			visit(startNode, &timer, childrenMap, timeRecordMap)
		} else {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	if x < 0 {
		return -1
	}

	found := false
	i := 0
	for i < len(childrenMap) {
		children := childrenMap[i]
		for j := 0; j < len(children); j++ {
			if children[j] == x {
				x = j + 1
				found = true
				break
			}
		}
		if found {
			i = 0
		} else {
			i++
		}
	}
	return x
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <bits/stdc++.h>
#define rep(i, a, b) for(int i = a; i < b; i++)
#define Rep(i, a, b) for(int i = a; i <= b; i++)
#define _GLIBCXX_DEBUG
#define Vl vector<ll>
#define Vs vector<string>
#define Vp vector<pair<ll, ll>>
#define ll long long
#define ALL(v) (v).begin(),(v).end()
using namespace std;
const double pi = acos(-1.0);
const ll MOD = 1e9 + 7;
const ll INF = 1LL << 60;

ll w[110][110];
ll d[110], f[110];
int color[110];
ll n, tt;
int White = 0, Gray = 1, Black = 2;

void dfs_visit(int u){
    int v;
    color[u] = Gray;
    d[u] = ++tt;
    Rep(v, 1, n){
        if(w[u][v] == 0) continue;
        if(color[v] == White){
            dfs_visit(v);
        }
    }
    color[u] = Black;
    f[u] = ++tt;
}

void dfs(){
    Rep(i, 1, n) color[i] = White; // 0:未訪問 1:訪問途中 2:訪問済
    
    tt = 0;
    Rep(u, 1, n){
        if(color[u] == White) dfs_visit(u);
    }

    Rep(i, 1, n){
        cout << i << " " << d[i] << " " << f[i] << endl;
    }

}

void solve() {
    cin >> n;
    Rep(i, 1, n) Rep(j, 1, n) w[i][j] = 0;
    Rep(i, 1, n){
        ll u, k; cin >> u >> k;
        rep(i, 0, k){
            ll v; cin >> v;
            w[u][v] = 1;
        }
    }

    dfs();

    return;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    solve();
    return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;
vector<vector<int>> adjlist;
int t=1;
vector<int> d;
vector<int> f;
void input(int n){
	vector<int> f={0,0};
	adjlist.push_back(f);
  for(int i=0;i<n;i++){
    vector<int> list;
    int ln;
    cin>>ln;
    list.push_back(ln);
    cin>>ln;
    list.push_back(ln);
    for(int j=0;j<ln;j++){
      int an;
      cin>>an;
      list.push_back(an);
    }
    adjlist.push_back(list);
  }
}

void depth_search(int id){
	vector<int> list=adjlist[id];
	for(int j=0;j<list[1];j++){
		if(d[list[2+j]]<0){
			d[list[2+j]]=++t;
			depth_search(list[2+j]);
		}
	}
	f[id]=++t;
}
 
void print(int n){
  for(int i=1;i<n+1;i++){
    cout<<i<<' '<<d[i]<<' '<<f[i]<<endl;
  }
}
int main(){
  int n;
  cin>>n;
	d=vector<int> (n+1,-1);
	f=vector<int> (n+1,-1);
	d[1]=1;
	f[1]=1;
  input(n);
  depth_search(1);
  print(n);
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)   for(int i=0;i<(n);++i)
#define SORT(c)    sort((c).begin(),(c).end())
#define CLR(a)     memset((&a), 0 ,sizeof(a))//clear memory
#define dump(x)    cerr << #x << " = " << (x) << endl;//debug
#define debug(x)   cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#define EPS        1e-10//sample:if((double)>=(double)+EPS)
//cin,cout release
//std::cin.tie(0);
//ios::sync_with_stdio(false);

using namespace std;
int n,v[100+1][100+1]={},color[100+1]={},tim,d[1000],f[1000];
void visit(int u){
  color[u]=1;
  d[u]=++tim;
  rep(i,n){
    if(v[u][i]==0)continue;
    if(color[i]==0)
      visit(i);
  }
  color[u]=2;
  f[u]=++tim;
}
void dfs(){
  rep(i,n)color[i]=0;
  tim = 0;
  rep(i,n){
    if(color[i]==0)
      visit(i);
  }
}

int main(){
  cin>>n;
  int u,k,in;
  rep(i,n){
    cin>>u>>k;
    rep(j,k){
      cin>>in;
      v[u-1][in-1]=1;
    }
  }
  dfs();
  rep(i,n)cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)

#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

stack<int> S;
int n, M[N][N];
int color[N], d[N], f[N], tt;
int nt[N]; //未訪問な次の頂点を保持

//未訪問な次の頂点を返す．全て訪問済みなら-1を返す
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 i){
    S.push(i);
    color[i] = GRAY;
    d[i] = ++tt;

    while(!S.empty()){
        int u = S.top();
        int v = next(u);
        if(v != -1){
            if(color[v] == WHITE){
                S.push(v);
                color[v] = GRAY;
                d[v] = ++tt;
            }
        }else{
            color[u] = BLACK;
            f[u] = ++tt;
            S.pop();
        }
    }
}

void dfs(){
    for(int i = 0; i < n; i++){
        color[i] = WHITE;
        nt[i] = 0;
    }
    tt = 0;

    for(int i = 0; i < n; i++){
        if(color[i] == WHITE) dfs_visit(i);
    }

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

}

int main(){
    int u, k, v;
    cin >> n;
    //隣接行列の作製
    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--; //0オリジンに変換
        for(int j = 0; j < k; j++){
            cin >> v;
            v--; //0オリジンに変換
            M[u][v] = 1;
        }
    }

    dfs();
    
    return 0;

}

C++: //Shunji Lin 08-144505

#include <iostream>

using namespace std;

bool adjmatrix[101][101]; //adjmatrix
int discover[101];
int processed[101];
int cur_time = 0;


void DFS(int vertex, int N) {
  cur_time++;
  discover[vertex] = cur_time; // set cost
  
  for (int i =1; i<= N; i++) {
    if(adjmatrix[vertex][i] && discover[i] == -1) {
      DFS(i, N);
    }
  }
  
  cur_time++;
  processed[vertex] = cur_time;
}


  
int main() {
  const int cur_time = 0;
  
  for (int i = 0; i < 101; i++) {
    discover[i] = -1; // upper limit
    processed[i] = -1;
  }
  int N;
  cin >> N;

  for (int i = 1; i <= N; i++) {
    int vertex, degree;
    cin >> vertex >> degree;

    for (int j = 0; j < degree; j++) {
      int outvertex;
      cin >> outvertex;
      adjmatrix[i][outvertex] = true;
    }
  }

  
  

  DFS(1,N);


  for (int i = 1; i <=N; i++) {
    if (discover[i] != -1) {
      cout << i << " " << discover[i] << " "<< processed[i] << endl;
    }
  }
}