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())

l=[[0 for i in range(n)] for j in range(n)]##静的確保 隣接行列
d=[0 for i in range(n)]##発見
f=[0 for i in range(n)]##完了
stack=[]##スタック
check=[]

for i in range(n):
    p=[int(x) for x in input().split()]
    
    for j in range(n):
        if j+1 in p[2:]:
            l[i][j]=1
##print("---隣接行列---")
##print(l)

time=1


while len(check)<n:
    for i in range(n):
        if i+1 not in check:
            stack+=[i+1]
            d[i]=time
            break
        else: pass

    while len(stack)!=0:
        print("----------while---------")
        for i in range(n):
            if l[stack[-1]-1][i]==1 and not i+1 in check and stack[-1]-1!=i:
                time+=1
                d[i]=time
                stack+=[i+1]

               ## print("stack:",stack)
               ## print("check:",check)
               ## print("d[",i,"]:",d[i])
                break
            elif i==n-1:
##最深    
                check+=[stack[-1]]
                time+=1
                f[stack.pop()-1]=time

               ## print("f[",i,"]:",f[i])
               ## print("check:",check)
    time+=1


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

Python: n = int(input())

from collections import deque

graph = [deque([]) for _ in range(n+1)]

for _ in range(n):
    u, k, *v = [int(x) for x in input().split()]

    v.sort()
    for i in v:
        graph[u].append(i)
    
arrive = [-1 for i in range(n+1)]
finish = [-1 for i in range(n+1)]

times = 0

def dfs(v):
    global times
    times += 1
    arrive[v] = times
    stack = [v]
    
    while stack:
        v = stack[-1]
        if graph[v]:
            w = graph[v].popleft()
            if arrive[w] == -1:
                times += 1
                arrive[w] = times
                stack.append(w)
        else:
            times += 1
            finish[v] = times
            stack.pop()
    return

for i in range(n):
    if arrive[i+1] == -1:
        dfs(i+1)

for j in range(n):
    tmp = [j+1, arrive[j+1], finish[j+1]]
    print(*tmp)

Python: n=int(input())
G=[[j for j in range(n)] for i in range(n)]
for i in range(n):
    g_in=list(map(int,input().split()))
    u=g_in[0]
    k=g_in[1]
    v=g_in[2:]
    for j in v:
        G[u-1][j-1]=1

visited=[0 for i in range(n)]
finished=[0 for i in range(n)]
L=[]
out=[[i+1,0,0] for i in range(n)]
step=0

def dfs(cn):
    flg=0
    if visited[cn]==0:
        flg=1
        L.append(cn)
    visited[cn]=1
    for i in range(n):
        if cn!=i and G[cn][i]==1 and visited[i]==0:
            dfs(i)
    if flg==1:
        L.append(cn)

i=0
while visited.count(1)<n:
    dfs(i)
    i+=1
copied=[0 for i in range(len(L))]

for i in range(len(L)):
    if copied[L[i]]==0:
        copied[L[i]]=1
        out[L[i]][1]=i+1
    elif copied[L[i]]==1:
        copied[L[i]]=2
        out[L[i]][2]=i+1

out=[' '.join(map(str,i)) for i in out]
#print(' '.join(map(str,[i+1 for i in L])))
print('\n'.join(map(str,out)))

Python: import sys
u=[]
k=[]
v=[]

time = 0

n=int(sys.stdin.readline().strip())
yattayatu=[False for i in range(n)]

s=[0 for i in range(n)]
f=[0 for i in range(n)]

for i in range(n):
	inp = sys.stdin.readline().strip().split(" ")
	inp = list(map(lambda x: int(x), inp))
	u.append(inp[0])
	k.append(inp[1])
	v.append(inp[2:])


def func(nodeid):
	global time
	if(yattayatu[nodeid-1]==True):
		return
	time += 1
	s[nodeid-1] = time
	for i in range(k[nodeid-1]):
		func(v[nodeid-1][i])
	time +=1
	f[nodeid-1]=time
	yattayatu[nodeid-1]=True

func(1)

for i in range(n):
	print(str(i+1)+" "+str(s[i])+" "+str(f[i]))

Python: def dfs(G, u, t, d, visited):
  found = t
  visited.add(u)
  t += 1
  for v in G[u]:
    if v not in visited:
      t = dfs(G, v, t, d, visited)
  complete = t
  d[u] = (found, complete)
  t+=1
  return t


n = int(input())
G = {}
for _ in range(n):
  entries = list(map(int, input().split(' ')))
  u = entries[0]
  k = entries[1]
  G[u] = set()
  for v in entries[2:]:
    G[u].add(v)


d = {}
dfs(G, 1, 1, d, set())
for i in sorted(d):
  print(i,d[i][0],d[i][1])

Python: n = int(input())
a = []
for i in range(n):
    a += [list(map(int, input().split()))[2:]]
cnt = 1
pre = [0]*n
aft = [0]*n
color = [0]*n
def dfs(s):
    global cnt
    pre[s-1] = cnt
    cnt += 1
    color[s-1] = 1
    for i in a[s-1]:
        if color[i-1] == 0:dfs(i)
    aft[s-1] = cnt
    cnt += 1

for i in range(n):
    if color[i] == 0:
        dfs(i+1)

for i in range(n):
    print(i+1, pre[i], aft[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(1,n+1):
        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

t = search(start, t)
for i in range(1,n+1):
    if color[i-1] == "white":
        t = search(i, t)

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