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()
}

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys

UNVISITED, VISITED_IN_STACK, POPPED_OUT = 0, 1, 2


def generate_adj_matrix(v_info):
    for v_detail in v_info:
        v_adj_list = v_detail[2:]
        # assert len(v_adj_list) == int(v_detail[1])
        for each in v_adj_list:
            init_adj_matrix[int(v_detail[0]) - 1][int(each) - 1] = 1
    return init_adj_matrix


def graph_dfs(v_init):
    global time

    # init the first node of overall graph iterations(times >= 1)
    vertices_visit_stack.append(v_init)
    vertices_status_list[v_init] = VISITED_IN_STACK
    vertices_d_time[v_init] += time
    # init end

    while len(vertices_visit_stack) > 1:
        current_vertex = vertices_visit_stack[-1]
        next_vertex = get_adj_vertices(vertex=current_vertex)

        if next_vertex:
            if vertices_status_list[next_vertex] is UNVISITED:
                vertices_status_list[next_vertex] = VISITED_IN_STACK
                time += 1
                vertices_d_time[next_vertex] += time
                vertices_visit_stack.append(next_vertex)
        else:
            vertices_visit_stack.pop()
            vertices_status_list[current_vertex] = POPPED_OUT
            time += 1
            vertices_f_time[current_vertex] += time

    return None


def get_adj_vertices(vertex):
    index = int(vertex) - 1
    for j in range(vertices_num):
        if adj_matrix[index][j]:
            adj_matrix[index][j] = 0
            return j + 1
    return None


def dfs_start():
    global time
    for i in range(vertices_num):
        if vertices_status_list[i + 1] == UNVISITED:
            # print('round: ', i + 1)
            graph_dfs(v_init=i + 1)
            time += 1


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertices_num = int(_input[0])
    vertices_info = list(map(lambda x: x.split(), _input[1:]))
    init_adj_matrix = [[0] * vertices_num for _ in range(vertices_num)]
    # assert len(vertex_info) == vertex_num

    # config length = (vertex_num + 1)
    vertices_visit_stack = [-1]
    vertices_status_list = [UNVISITED] * vertices_num
    vertices_status_list.insert(0, -1)
    vertices_d_time, vertices_f_time = ([0] * (vertices_num + 1) for _ in range(2))

    adj_matrix = generate_adj_matrix(vertices_info)
    # timing start from 1
    time = 1
    dfs_start()
    for k in range(vertices_num):
        print(k + 1, vertices_d_time[k + 1], vertices_f_time[k + 1])

Python: n=int(input())
ne=[[] for _ in range(n+1)]
for _ in range(n):
    u,k,*v=map(int,input().split())
    ne[u]=v

class dfs:
    def __init__(self, n, ne):
        self.n=n
        self.ne=ne
        self.d=[0]*(n+1)
        self.f=[0]*(n+1)
        self.t=0
    def search(self, a):
        self.t+=1
        self.d[a]=self.t
        for p in ne[a]:
            if self.d[p]==0:
                self.search(p)
        self.t+=1
        self.f[a]=self.t
DFS=dfs(n,ne)
for i in range(1,n+1):
    if DFS.d[i]==0:
        DFS.search(i)
    print(i,DFS.d[i],DFS.f[i])

Python: #coding: utf-8

n = int(input())
color = ["white" for i in range(n)]
d = [[] for i in range(n)]
global t
t = 0
M = [[False for i in range(n)] for j in range(n)]
for i in range(n):
    data = list(map(int,input().split()))
    u = data[0]
    k = data[1]
    if i == 0:
        start = u
    for v in data[2:2+k]:
        M[u-1][v-1] = True


def search(u,t):
    t += 1
    color[u-1] = "gray"
    d[u-1].append(t)
    for v in range(n):
        if M[u-1][v-1] and color[v-1] == "white":
            t = search(v,t)
    color[u-1] = "black"
    t += 1
    d[u-1].append(t)
    return t

search(start, t)
for i in range(n):
    print(i+1, d[i][0], d[i][1])

Python: def depth_search(u, t):
    t += 1
    s.append(u)
    d[u] = t
    for v in range(N):
        if adjacency_list[u][v] == 0:
            continue 
        if d[v] == 0 and v not in s:
            t = depth_search(v, t)
    t += 1
    s.pop()
    f[u] = t
    return t

N = int(input())
adjacency_list = [[0 for j in range(N)] for i in range(N)]
for _ in range(N):
    u, k, *v = input().split()
    for i in v:
        adjacency_list[int(u)-1][int(i)-1] = 1

s = []
d = [0 for _ in range(N)]
f = [0 for _ in range(N)]

t = 0
for u in range(N):
    if d[0] == 0:
        t = depth_search(u, t)

for i in range(N):
    print("{} {} {}".format(i+1, d[i], f[i]))

Python: import sys
sys.setrecursionlimit(10 ** 9)

N = int(input())
graph = list()
for i in range(N):
  x = list(map(int, input().split()))
  graph.append(x[2:])

start = [0] * N
end = [0] * N
visited = [False] * N
time = 0
def dfs(n):
  if visited[n]:
    return
  visited[n] = True
  global time
  time += 1
  start[n] = time
  for i in graph[n]:
    dfs(i-1)
  time += 1
  end[n] = time

for i in range(N):
  dfs(i)
for i in range(N):
  print(i+1, start[i], end[i])