Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

Python: N = int(input())
UKV = [list(map(int,input().split())) for _ in range(N)]

seen = [False]*N
first_time = [-1]*N
last_time = [-1]*N
time = 0
def dfs(G, v):
    global seen
    global first_time
    global last_time
    global time
    seen[v-1] = True
    time += 1
    first_time[v-1] = time
    for next_v in G[v]:
        if seen[next_v-1]:
            continue
        dfs(G, next_v)
    time += 1
    last_time[v-1] = time

G = {}
for ukv in UKV:
    G[ukv[0]] = sorted(ukv[2:])
for i in range(1,N+1):
    if seen[i-1]:
        continue
    dfs(G, i)

for i in range(1,N+1):
    print(i,first_time[i-1],last_time[i-1])

Python: G = {}
for _ in range(int(input())):
  x = list(map(int, input().split()))
  G[x[0]] = sorted(x[2:])

t = 1
stack = [1]
timestamp = {1:[t]}

while len(stack) > 0:
  t += 1
  v = stack[-1]

  while len(G[v]) > 0:
    v = G[v].pop(0)
    if v in timestamp: continue
    stack.append(v)
    timestamp[v] = [t]
    break
  else:
    v = stack.pop()
    timestamp[v].append(t)

for i in timestamp:
  print(i, *timestamp[i])

Python: import sys

time = 0
def dfs(u):
    global time
    flag_list[u] = 1
    time += 1
    d_list[u] = time
    for v in range(n):
        if m_list[u][v] == 1 and flag_list[v] == 0:
            dfs(v)
    flag_list[u] = 2
    time += 1
    f_list[u] = time


input = sys.stdin.readline
n = int(input())
m_list = [[0]*n for _ in range(n)]
for _ in range(n):
    input_list = list(map(int, input().split()))
    index = input_list[0] - 1
    if input_list[1] > 0:
        for a in input_list[2:]:
            m_list[index][a-1] = 1
    
d_list = [0]*n
f_list = [0]*n
flag_list = [0]*n # 0: 未到達, 1: 処理中, 2: 完了
for i in range(n):
    if flag_list[i] == 0:
        dfs(i)

for i in range(n):
    print(i+1, d_list[i], f_list[i])

Python: G = {}
N = int(input())
for _ in range(N):
    L = list(map(int, input().split()))
    G[L[0]] = L[2:]

# print(G)
d = [-1] * N
f = [-1] * N
q = [1]
visited = [False] * N

time = 1


def dfs(v):
    global time
    visited[v-1] = True

    for nv in G[v]:
        if d[nv-1] < 0:
            d[nv-1] = time
            time += 1
        if not visited[nv-1]:
            dfs(nv)

    f[v-1] = time
    time += 1


for i in range(1, N+1):
    if not visited[i-1]:
        d[i-1] = time
        time += 1
        dfs(i)

for i in range(N):
    print(i+1, d[i], f[i])

Python: import math
import copy
import sys
import fractions
# import numpy as np
# import statistics
import decimal
import heapq
import collections
import itertools
import bisect


# from operator import mul

# sys.setrecursionlimit(100001)


# input = sys.stdin.readline
# sys.setrecursionlimit(10**6)

# ===FUNCTION===

def getInputIntList():
    outputDataList = []
    inputData = input().split()
    outputDataList = [int(n) for n in inputData]

    return outputDataList


def getSomeInputInt(n):
    outputDataList = []
    for i in range(n):
        inputData = int(input())
        outputDataList.append(inputData)

    return outputDataList


def getSomeInputListInt(n):
    inputDataList = []
    outputDataList = []
    for i in range(n):
        inputData = input().split()
        inputDataList = [int(n) - 1 for n in inputData]
        outputDataList.append(inputDataList)

    return outputDataList


# ===CODE===

n = int(input())

data = getSomeInputListInt(n)

ans = [[] for _ in range(n)]

edge = []
for d in data:
    edge.append(d[2:])


def dfs(i, cnt):
    if len(ans[i]) > 0:
        return cnt

    cnt += 1

    ans[i].append(cnt)
    for j in range(len(edge[i])):
        cnt = dfs(edge[i][j], cnt)

    cnt += 1
    ans[i].append(cnt)

    return cnt

tmp = 0
for i in range(n):
    tmp = dfs(i, tmp)

for i in range(n):
    print(i + 1, *ans[i], sep=" ")

Python: class Node:
    def __init__(self, data):
        self.data = data
        self.neighbors = list()
        self.find_time = 0
        self.end_time = 0

N = int(input())
work_id = 0
nodes = list()
nodes.append(Node(0))


for _ in range(N):
    tmp_list = list( map(int, input().split()) )
    node = Node(tmp_list[0])
    for i in range(tmp_list[1]):
        node.neighbors.append(tmp_list[i+2])
    nodes.append(node)
    nodes[0].neighbors.append(node.data)

# for node in nodes:
#     print(node.data, ":", node.neighbors)


def search(node):
    global work_id

    if node.find_time != 0:
        return
    
    if node.data != 0:
        work_id += 1
        node.find_time = work_id

    if len(node.neighbors) > 0:
        for neighbor in node.neighbors:
            search(nodes[neighbor])
    
    if node.data != 0:
        work_id += 1
        node.end_time = work_id

search(nodes[0])

for node in nodes:
    if node.data == 0: continue
    print(node.data, node.find_time, node.end_time)