Go: package main

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

var N int
var A [][]int
var t int
var color, d, f []int

const (
	WHITE = iota
	GRAY
	BLACK
)

func dfsVisit(u int) {
	color[u] = GRAY
	t ++
	d[u] = t
	for v:=0; v<N; v++ {
		if A[u][v] == 0 {
			continue
		}
		if color[v] == WHITE {
			dfsVisit(v)
		}
	}
	color[u] = BLACK
	t++
	f[u] = t
}

func dfs() {
	for u:=0; u<N; u++ {
		if color[u] == WHITE {
			dfsVisit(u)
		}
	}
	for u:=0; u<N; u++{
		fmt.Printf("%d %d %d\n", u+1, d[u], f[u])
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	color = make([]int, N)
	d = make([]int, N)
	f = make([]int, N)
	A = make([][]int, N)
	for i:=0; i<N; i++{
		A[i] = make([]int, N)
	}
	for i:=0; i<N; i++{
		index := nextInt(scanner) - 1
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			v := nextInt(scanner) - 1
			A[index][v] = 1
		}
	}
	dfs()
}

Python: class Node(object):
    def __init__(self, V):
        self.V = V
        self.find_time = 0
        self.finish_time = 0
        self.is_finded = False
  
  
n = int(input())
nodes = [0] * 101
for i in range(n):
    data = input().split()
    V = list(map(int, data[2:]))
    V.sort(reverse = True)
    nodes[int(data[0])] = Node(V)
  
find_q = []
find_q.append(1)
cnt = 1
q_size = len(find_q)
while q_size != 0:
    #print(find_q)
    node = nodes[find_q[q_size -1]]
  
    if node.is_finded == False:
        node.find_time = cnt
        cnt += 1
        node.is_finded = True
        if len(node.V) == 0:
            node.finish_time = cnt
            cnt += 1
            find_q.pop()
            q_size = len(find_q)
        else:
            f = 0
            for x in node.V: 
                if nodes[x].is_finded == False:
                    f = 1
                    if x in find_q:
                        find_q.remove(x)
                    if nodes[x].finish_time == 0: 
                        find_q.append(x)
            
            if f == 0:  # didnt append nodes
                node.finish_time = cnt
                cnt += 1
                find_q.pop()
                q_size = len(find_q) 
            else :    
                q_size = len(find_q)
  
    else:   #node is finded 
        node.finish_time = cnt
        cnt += 1
        find_q.pop()
        q_size = len(find_q)
        continue
  
for i in range(1, n+1):
    if not isinstance(nodes[i], int):
        print(i, nodes[i].find_time, nodes[i].finish_time)

Python: n = int(input())
graph = [list(map(int, input().split())) for i in range(n)]

v_color = ["WHITE"] * (n+1) # WHITE:????¨???????GRAY:?¨??????????BLACK:??¢?´¢??????
d = [0] * (n+1)
f = [0] * (n+1)
stack = []

def DFS(u):
    time = 0
    stack.append(u)
    
    while stack != []:
        u = stack[-1]
        time += 1
        
        v_color[u] = "GRAY"
        if d[u] == 0:
            d[u] = time
        
        for Next in graph[u-1][2:]:
            if v_color[Next] == "WHITE":
                stack.append(Next)
                break
        
        else:
            v_color[u] = "BLACK"
            f[u] = time +1
            stack.pop()
        
DFS(1)
    
for i in range(1,n+1):
    print(i,d[i],f[i])

Python: n = int(input())

adj = [0]*n # adjacent list

for i in range(n):
    tmp = list(map( int, input().split() ) )
    adj[tmp[0]-1] = list(map(lambda x : x - 1, tmp[2:]))

c = ['w']*n # color of each vertex
d = [0]*n # discovery time for each vertex
f = [0]*n  # finish time for each vertex
time = 0

def DFS_visit(u):
    global time
    time += 1
    d[u] = time
    c[u] = 'g'
    for v in adj[u]:
        if c[v] == 'w':
            DFS_visit(v)
    c[u] = 'b'
    time += 1
    f[u] = time
    
for u in range(n):
    if c[u] == 'w':
        DFS_visit(u)

Python: n = int(raw_input())

d = [0 for i in range(n)]
f = [0 for i in range(n)]
a = [[0 for i in range(n)] for j in range(n)]
st = [0 for i in range(n)]
time = [0]
G = [0 for i in range(n)]

def dfs_visit(s):
    st[s] = 1
    time[0] += 1
    d[s] = time[0]
    
    for k in range(n):  
      if a[s][k] == 1 and st[k] == 0:
          dfs_visit(k)
    time[0] += 1
    f[s] = time[0]

def main():
    for s in range(n):
        if st[s] == 0:
            def_visit(s)
    for s in range(n):
        print(s+1,d[s],f[s]) 

for i in range(n):
  G = map(int, raw_input().split())
  for j in range(G[1]):
    v[G[0]-1][G[2+j]-1] = 1
   
main()

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

import sys

UNVISITED, VISITED_IN_STACK, POPPED_OUT = 0, 1, 2


def generate_adj(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)
    vertex_visit_stack.append(v_init)
    vertex_status_list[v_init] = VISITED_IN_STACK
    vertex_d_time[v_init] += time
    # init end
    while len(vertex_visit_stack) > 1:
        current_vertex = vertex_visit_stack[-1]
        next_vertex = get_next_vertex(node=current_vertex)
        # print(current_vertex, next_vertex, vertex_status_list, vertex_visit_stack)
        time += 1
        if next_vertex and vertex_status_list[next_vertex] is UNVISITED:
            # print('on', current_vertex, next_vertex)
            vertex_status_list[next_vertex] = VISITED_IN_STACK
            vertex_d_time[next_vertex] += time
            vertex_visit_stack.append(next_vertex)
        else:
            # other_vertex = get_next_vertex(current_vertex)
            # print('stuck', current_vertex, other_vertex)
            vertex_visit_stack.pop()
            vertex_status_list[current_vertex] = POPPED_OUT
            vertex_f_time[current_vertex] += time

    return None


def get_next_vertex(node):
    for j in range(vertex_num):
        if adj_matrix[int(node) - 1][j]:
            adj_matrix[int(node) - 1][j] = 0
            return j + 1


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


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertex_num = int(_input[0])
    vertex_info = list(map(lambda x: x.split(), _input[1:]))
    init_adj_matrix = [[0] * vertex_num for _ in range(vertex_num)]
    # assert len(vertex_info) == vertex_num
    # config length -> (vertex_num + 1)
    vertex_visit_stack = [-1]
    vertex_status_list = [UNVISITED] * vertex_num
    vertex_status_list.insert(0, -1)
    vertex_d_time, vertex_f_time = ([0] * (vertex_num + 1) for _ in range(2))

    adj_matrix = generate_adj(vertex_info)

    time = 1
    dfs_start()

    for k in range(vertex_num):
        print(k + 1, vertex_d_time[k + 1], vertex_f_time[k + 1])