Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Scan()
	num, _ := strconv.Atoi(sc.Text())
	nodes := make(map[int]*node)

	for i := 0; i < num; i++ {
		sc.Scan()
		id, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		nodeNum, _ := strconv.Atoi(sc.Text())
		n := node{id, make([]int, 0), 0, 0}
		for j := 0; j < nodeNum; j++ {
			sc.Scan()
			nid, _ := strconv.Atoi(sc.Text())
			n.nexts = append(n.nexts, nid)
		}
		nodes[id] = &n
	}

	s := Stack{}
	for i := 1; i < len(nodes)+1; i++ {
		if nodes[i].s != 0 {
			continue
		}
		walk(i, &nodes, s)
	}
	for i := 1; i < len(nodes)+1; i++ {
		fmt.Printf("%v %v %v\n", (*nodes[i]).id, (*nodes[i]).s, (*nodes[i]).e)
	}
}

var time int

func walk(nid int, nodes *map[int]*node, s Stack) {
	n := (*nodes)[nid]
	if n.s != 0 {
		return
	}
	time++
	n.s = time
	s.Push(n)
	for _, v := range n.nexts {
		walk(v, nodes, s)
	}
	time++
	n.e = time
}

type node struct {
	id    int
	nexts []int
	s     int
	e     int
}

// Stack is Stack
type Stack struct {
	stack []interface{}
}

// Push new value
func (stack *Stack) Push(val interface{}) {
	stack.stack = append(stack.stack, val)
}

// Pop new value
func (stack *Stack) Pop() interface{} {
	val := stack.stack[len(stack.stack)-1]
	stack.stack = stack.stack[0 : len(stack.stack)-1]
	return val
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;

#define rep(i, n) for (int i = 0; i < n; ++i)
#pragma region Debug
template <typename T>
void view(const std::vector<T> &v)
{
    for (const auto &e : v)
    {
        std::cout << e << " ";
    }
    std::cout << std::endl;
}
template <typename T>
void view(const std::vector<std::vector<T>> &vv)
{
    for (const auto &v : vv)
    {
        view(v);
    }
}
#pragma endregion

vector<vector<int>> g;
vector<int> d, f;

int dfs(int v, int t)
{
    // cout << v << " ";
    if (f[v] != INT32_MAX)
    {
        return f[v];
    }
    if (d[v] != INT32_MAX && f[v] == INT32_MAX)
    {
        return t - 1;
    }

    d[v] = min(d[v], t);

    int tt = t + 1;
    for (auto to : g[v])
    {
        if (v == to)
            continue;
        tt = max(tt, dfs(to, tt) + 1);
    }
    f[v] = min(tt, f[v]);

    return tt;
}

int main()
{
    int n;
    cin >> n;
    g = vector<vector<int>>(n, vector<int>());
    d = vector<int>(n, INT32_MAX);
    f = vector<int>(n, INT32_MAX);

    rep(i, n)
    {
        int k;
        cin >> k >> k;
        rep(j, k)
        {
            int t;
            cin >> t;
            t--;
            g[i].emplace_back(t);
        }
    }

    int t = 1;
    rep(i, n)
    {
        if (f[i] == INT32_MAX)
        {
            t = dfs(i, t) + 1;
        }
    }

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

    return 0;
}

C++: #include<stdio.h>

int d[100],f[100],n,g[100][100],time=1;

int func(int m){
    d[m]=time++;
    int i,j;
    for(i=0;i<n;i++){
        if(g[m][i]==1 && d[i]==0){
            func(i);
        }
    }
    f[m]=time++;
}

int main(void){
    int i, j, u, k, v;
    scanf("%d",&n);
    for(i=0;i<n;i++){
        scanf("%d %d",&u,&k);
        for(j=0;j<k;j++){
            scanf("%d",&v);
            g[u-1][v-1]=1;
        }
    }
    func(0);
    for(i=0;i<n;i++){
        if(d[i]==0){
            func(i);
        }
    }
    for(i=0;i<n;i++){
        printf("%d %d %d\n",i+1,d[i],f[i]);
    }
    return 0;
}

C++: #include<iostream>
#include<algorithm>

using namespace std;

int g[101][101];
int d[101], f[101];
int t = 0, n;

int dfs(int x){
    t++;
    for(int i=1; i<=n; i++){
        if(d[x] == 0) d[x] = t;
       
        if(g[x][i] == 1 && f[i] == 0){
            dfs(i);
            t++;   
        }
        
        if(i==n && f[x] == 0){
            f[x] = t+1;
        }
    }
    return 0;        
  
}

int main(){
    cin >> n;

    for(int i=1; i<=n; i++){
        for(int j=1; j<=n; j++){
            g[i][j] = 0;
        }
        d[i] = 0;
        f[i] = 0;
    }
    
    int u,k;
    for(int i=0; i<n; i++){
        cin>>u>>k;
        for(int j=0; j<k; j++){
            int v;
            cin>>v;
            g[u][v] = 1;
        }
    }

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

C++: #include <iostream>
#include<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<array>
#include<iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
typedef int long long ll;

using namespace std;
static const int N=100;
static const int WHITE =0;
static const int GRAY=1;
static const int BLACK=2;
int n,M[N][N];//グラフの隣接行列
int color[N],d[N],f[N],tt;//状態
int nt[N];

int next(int u){
    
    for(int v=nt[u];v<n;v++){
        nt[u]=1;
        if(M[u][v])return v;
    }
    return -1;
}


void dfs_visit(int r){
    
    for(int i=0;i<n;i++)nt[i]=0;
    
    stack<int> S;
    S.push(r);
    color[r]=GRAY;
    d[r]=++tt;
    
    while(!S.empty()){
        int u=S.top();
        int v=next(u);
        if(v!=-1){
            if(color[v]==WHITE){
                color[v]=GRAY;
                d[v]=++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[u]=BLACK;
            f[u]=++tt;
        }
    }
    
    
}

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






int main(){

    int u,k,v;
    cin>>n;
    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--;
        for(int j=0;j<k;j++){
            cin>>v;
            v--;
            M[u][v]=1;
        }
    }
    
    
    
    dfs();
    
    
    
    
    

return 0;
}

C++: /*d[n]で最初に発見した時刻を出していき、
f[n]で戻りながら完了時刻をいれていく書き方*/
#include <iostream>
using namespace std;

int r[101][101];
int d[101], f[101], num, visit[101], p=0;

void dfs(int n){
    if(!visit[n]){
        visit[n]++;
        d[n] = ++p;
        for(int i=1; i<num+1; i++)
            if(r[n][i]) dfs(i);
        f[n] = ++p;
    }
}

int main(void){
    int u, k, v;
    cin >> num;
    for(int i=0; i<num; i++){
        cin >> u >> k;
        for(int j=0; j<k; j++){
            cin >> v;
            r[u][v]++;
        }
    }
    for(int i=1; i<num+1; i++){
        if(!visit[i]) dfs(i);
    }
    for(int i=1; i<num+1; i++)
        cout << i << " " << d[i] << " " << f[i] << endl;
}

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

using namespace std;

int N;
vector<vector<int>> tree;
vector<pair<int,int>> times;

void stamp(int ind, int &time){
	//cout << ind << "," << time << endl;
	if(times[ind].first == 0) times[ind].first = time++;
	else return;
	if(tree[ind].size() == 0){
		times[ind].second = time++;
		//cout<<"break! " << ind << endl;
		return;
	}
	for(int i=0;i<tree[ind].size();i++){
		//cout << tree[ind][i] << endl;
		stamp(tree[ind][i],time);
	}
	//cout << ind << ":" << time << endl;
	times[ind].second = time++;
	if(ind == 1){
		for(int i=2;i<=N;i++){
			stamp(i,time);
		}
	}
}

int main(){
	cin >> N;
	tree = vector<vector<int>>(N+1);
	times = vector<pair<int,int>>(N+1,make_pair(0,0));

	for(int i=1;i<N+1;i++){
		int ind, branch;
		cin >> ind >> branch;
		vector<int> tmp(branch);
		for(int j=0;j<branch;j++){
			int in;
			cin >> in;
			tmp[j] =  in;
		}
		tree[ind] = tmp;
	}

	int time = 1;
	stamp(1,time);

	int i = 1;
	for(auto st:times){
		if(i<=N)
			cout << i << " " << times[i].first << " " << times[i].second << endl;
		i++;
	}

	return 0;
}