Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const N = 100

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph struct {
	M               [N][N]int
	color, d, f, nt [N]int
	tt              int
}

func (g *Graph) next(u, n int) int {
	for v := g.nt[u]; v < n; v++ {
		g.nt[u] = v + 1
		if g.M[u][v] != 0 {
			return v
		}
	}
	return -1
}

func (g *Graph) dfsVisit(r, n int) {
	var S []int
	S = append([]int{r}, S...)
	g.color[r] = GRAY
	g.tt++
	g.d[r] = g.tt

	for len(S) != 0 {
		u := S[0]
		v := g.next(u, n)
		if v == -1 {
			S = S[1:]
			g.color[u] = BLACK
			g.tt++
			g.f[u] = g.tt
			continue
		}

		if g.color[v] != WHITE {
			continue
		}

		g.color[v] = GRAY
		g.tt++
		g.d[v] = g.tt
		S = append([]int{v}, S...)
	}
}

func (g *Graph) dfs(n int) string {
	for i := 0; i < n; i++ {
		g.color[i] = WHITE
	}
	g.tt = 0

	for u := 0; u < n; u++ {
		if g.color[u] == WHITE {
			g.dfsVisit(u, n)
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d %d %d\n", i+1, g.d[i], g.f[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	var g Graph
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		u--
		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			v--
			g.M[u][v] = 1
		}
	}

	return g.dfs(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

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

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

int main ()
{
    int N;
    cin >> N;

    int M[N][N];
    int D[N], F[N], C[N];

    for (int i = 0; i < N; i++)
    {
        D[i] = 0;
        F[i] = 0;
        C[i] = WHITE;
        
        for (int j = 0; j < N; j++)
        {
            M[i][j] = 0;
        }
    }

    for (int i = 0; i < N; i++)
    {
        int u, k;
        cin >> u >> k;
        u--;

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


    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            if (j > 0)
                cout << " ";
            cout << M[i][j];
        }
        cout << endl;
    }

    stack<int> *S = new stack<int>;

    int time = 0;

    S->push(0);
    C[0] = GRAY;
    D[0] = ++time;

    while (S->size() > 0)
    {
        int u = S->top();
        int v = -1;

        // next 
        for (int i = 0; i < N; i++)
        {
            int flag = M[u][i];

            if (flag == 1)
            {
                if (C[i] == WHITE)
                {
                    v = i;
                    break;
                }
            }
        }

        if (v != -1)
        {
            if (C[v] == WHITE)
            {
            C[v] = GRAY;
            D[v] = ++time;
            S->push(v);
            }
        }
        else
        {
            S->pop();
            C[u] = BLACK;
            F[u] = ++time;
        }
    }

    for (int i = 0; i < N; i++)
    {
        cout << i + 1 << " " << D[i] << " " << F[i] << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define MAX 101
int m[MAX][MAX],d[MAX],f[MAX],tt,n,book[MAX];

void dfs_vis(int s)
{
	book[s]=0;
	d[s]=++tt;
	for(int i=1;i<=n;i++)
	{
		if(!m[s][i]) continue;
		if(book[i]) dfs_vis(i);
	}
	f[s]=++tt;
}

void dfs()
{
	for(int i=1;i<=n;i++) book[i]=1;
	for(int i=1;i<=n;i++) if(book[i]) dfs_vis(i);
	for(int i=1;i<=n;i++) cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
}
int main()
{
	int u,k,t;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		cin>>u>>k;
		for(int j=0;j<k;j++)
		{
			cin>>t;
			m[u][t]=1;
		}
	}	
	dfs();
	return 0;
}

C++: #include<iostream>
#include<stack>
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, tt;
int M[N][N], color[N], d[N], f[N], nt[N]; 

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;
		for(v = 0; v < n; v++) {
			if(M[u][v] == 0) continue;
			if(color[v] != WHITE) continue;
			break; 
		}
		if(v != n) {
			if(color[v] == WHITE) {
			   color[v] = GRAY;
			   d[v] = ++tt;
			   S.push(v); 	
		    }
		} 
		for(v = 0; v < n; v++) {
			if(M[u][v] == 1) break;
		}
		if(v == n){
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


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

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

int main() {
	int k , u, 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 i = 0; i < k; i++) {
	        cin >> v;
	        v--;
		   M[u][v] = 1; 
     	}
	} 
	
	dfs();
	
	return 0;
}

C++: #include <iostream>
#include <utility>
#define N 	100

using namespace std;

int T[N+1][N+1];
pair<int , int> M[N+1];
int t = 0;

void init(){
	for (int i = 0; i < 100; ++i)
	{
		M[i].first = 0;
		M[i].second = 0;
		for (int j = 0; j < 100; ++j)
		{
			T[i][j] = 0;
		}
	}
}

void DispTable(int n){
	for (int i = 1; i <= n; ++i)
	{
		for (int j = 1; j <= n; ++j)
		{
			cout << T[i][j];
			if(j!=n) cout << " ";
		}
		cout << endl;
	}
}

void DispM(int n){
	for (int i = 1; i<=n; i++)
	{
		cout << i << " " << M[i].first << " " << M[i].second << endl;
	}
}

void dfs(int cur,int n){
	t++;
	M[cur].first = t;
	// cerr << "visiting " << cur << " " << t << endl;

	for (int i = 1; i <= n; ++i)
	{
		if(i != cur && T[cur][i] == 1 && M[i].first == 0) dfs(i,n);
	}
	t++;
	M[cur].second = t;
}

int main(){
	int n;
	cin >> n;
	init();
	for (int i = 0; i < n; ++i)
	{
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			int v;
			cin >> v;
			T[u][v] = 1;	
		}
	}
	// DispTable(n);
	dfs(1,n);
	DispM(n);
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

// macro
#define rep(i,n) for(i=0;i<n;i++)
#define ll long long
#define all(v) v.begin(), v.end()

// code starts
int times=1;

void dfs(int now,vector<int> &fvisit,vector<int> &fin, vector<vector<int>> &vs)
{
  if(fvisit[now]==-1)
  {
    fvisit[now]=times;
    times++;
  }
  else return;
  int i;
  rep(i,vs[now].size())
  {
    if(fvisit[vs[now][i]]==-1)
    {
      dfs(vs[now][i],fvisit,fin,vs);
    }
  }
  fin[now]=times;
  times++;
}

int main()
{
  int n;cin>>n;
  vector<vector<int>> vs(n);
  int i,j;
  rep(i,n)
  {
    int u,k;cin>>u>>k;
    u--;
    rep(j,k)
    {
      int vj;cin>>vj;
      vj--;
      vs[u].emplace_back(vj);
    }
  }
  vector<int> fvisit(n,-1);
  vector<int> fin(n,-1);
  rep(i,n)
  {
    dfs(i,fvisit,fin,vs);
  }
  rep(i,n)
  {
    cout<<i+1<<' '<<fvisit[i]<<' '<<fin[i]<<endl;
  }
}