Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Scan()
	num, _ := strconv.Atoi(sc.Text())
	nodes := make(map[int]*node)

	for i := 0; i < num; i++ {
		sc.Scan()
		id, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		nodeNum, _ := strconv.Atoi(sc.Text())
		n := node{id, make([]int, 0), 0, 0}
		for j := 0; j < nodeNum; j++ {
			sc.Scan()
			nid, _ := strconv.Atoi(sc.Text())
			n.nexts = append(n.nexts, nid)
		}
		nodes[id] = &n
	}

	s := Stack{}
	for i := 1; i < len(nodes)+1; i++ {
		if nodes[i].s != 0 {
			continue
		}
		walk(i, &nodes, s)
	}
	for i := 1; i < len(nodes)+1; i++ {
		fmt.Printf("%v %v %v\n", (*nodes[i]).id, (*nodes[i]).s, (*nodes[i]).e)
	}
}

var time int

func walk(nid int, nodes *map[int]*node, s Stack) {
	n := (*nodes)[nid]
	if n.s != 0 {
		return
	}
	time++
	n.s = time
	s.Push(n)
	for _, v := range n.nexts {
		walk(v, nodes, s)
	}
	time++
	n.e = time
}

type node struct {
	id    int
	nexts []int
	s     int
	e     int
}

// Stack is Stack
type Stack struct {
	stack []interface{}
}

// Push new value
func (stack *Stack) Push(val interface{}) {
	stack.stack = append(stack.stack, val)
}

// Pop new value
func (stack *Stack) Pop() interface{} {
	val := stack.stack[len(stack.stack)-1]
	stack.stack = stack.stack[0 : len(stack.stack)-1]
	return val
}

Python: def dfs():
    tt = 0
    for u in range(N):
        if colors[u] == WHITE:
            tt = dfs_visit(u, tt)

def dfs_visit(u, tt):
    tt += 1
    colors[u] = GLAY
    d[u] = tt
    for v in range(N):
        if adjacency_list[u][v] == 1 and colors[v] == WHITE:
            tt = dfs_visit(v, tt)
    tt += 1
    colors[u] = BLACK
    f[u] = tt
    return tt


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

WHITE = 0
GLAY = 1
BLACK = 2
colors = [WHITE for _ in range(N)]
d = [0 for _ in range(N)]
f = [0 for _ in range(N)]

dfs()

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

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: import sys
sys.setrecursionlimit(10**9)
from collections import deque

n = int(input())
u = [[] for i in range(n+1)] #隣接リスト
for i in range(n):
    v = list(map(int, input().split()))
    u[v[0]] = v[1:] #v = [次数, 頂点...]

d = [-1] * (n+1)
f = [-1] * (n+1)
visited = [False] * (n+1)
visited[0] = True
time = 1

#再帰
def dfs(c):
    global time
    d[c] = time
    time += 1
    visited[c] = True
    for i in range(1, u[c][0]+1):
        if not visited[u[c][i]]:
            dfs(u[c][i])
    f[c] = time
    time += 1
"""
探索は元の始点から到達可能なすべての頂点を発見するまで続き、
未発見の頂点が残っていれば、
その中の番号が一番小さい１つを新たな始点として探索を続けます。
"""
while False in visited:
    dfs(visited.index(False))

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

Python: def dfs_time(G, s):
    # ?????????
    color = {key: 'White' for key in G.keys()}
    d = {key: 0 for key in G.keys()}
    f = {key: 0 for key in G.keys()}

    # ????????????
    S = [s]
    color[s] = 'Gray'
    time = 1
    d[s] = time

    while len(S) > 0:
        u = S[-1]
        v_list = G[u]
        if v_list:
            v = v_list.pop()
        else: v = None
        if v is not None:
            if color[v] == 'White':
                color[v] = 'Gray'
                time += 1
                d[v] = time
                S.append(v)
        else:
            S.pop()
            color[u] = 'Black'
            time += 1
            f[u] = time

    return d, f


if __name__ == '__main__':
    G = {}
    n = int(input())
    for _ in range(n):
        tmp = list(map(int, input().split()))
        u = tmp.pop(0)
        k = tmp.pop(0)
        G[u] = tmp

    d, f= dfs_time(G, 1)

    for node in G:
        print('{0} {1} {2}'.format(node, d[node], f[node]))

Python: # coding: UTF-8
from collections import deque
#入力値の整理
n = int(input())
adj={}
visited={}
d={}
f={}
t=0
for i in range(n):
  raw=list(map(int,input().split()))
  u = raw.pop(0)
  k = raw.pop(0)
  raw.sort()
  q = deque(raw)
  adj[u] = q
  visited[u] = False
  d[u] = -1
  f[u] = -1

next = 1
v = next
d[next] = t + 1
stack = deque()

while True:
  t = t+1
  clear = True
  while adj[v]:
    cand = adj[v].popleft()
    if not visited[cand]:
      next = cand
      d[cand] = t + 1
      visited[cand] = True
      clear = False
      break
  if clear:
    f[v] = t + 1
    if stack:
      next = stack.pop()
      v = next
    else:
      break
  else:
    stack.append(v)
    v = next

#print
i = 0
for j in range(n):
  i += 1
  print(str(i) + " " + str(d[i]) + " " + str(f[i]))

#return d,f

Python: import sys
from collections import defaultdict


time = 1


def dfs(g, visited, start, ans):
    global time
    visited[start - 1] = True
    ans[start - 1][0] = time
    for e in g[start]:
        if not visited[e - 1]:
            time += 1
            dfs(g, visited, e, ans)
    time += 1
    ans[start - 1][1] = time


def main():
    input = sys.stdin.buffer.readline
    n = int(input())
    g = defaultdict(list)
    for i in range(n):
        line = list(map(int, input().split()))
        if line[1] > 0:
            g[line[0]] = line[2:]
    visited = [False] * n

    ans = [[1, 1] for _ in range(n)]
    global time
    while False in visited:
        start = visited.index(False) + 1
        dfs(g, visited, start, ans)
        time += 1

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


if __name__ == "__main__":
    main()

Python: from sys import stdin
n = int(stdin.readline())
M = [None] + [list(map(int, stdin.readline().split()[2:])) for i in range(n)]
sndf = [None] + [[False, i] for i in range(1, n + 1)]
tt = 0
def dfs(u):
    global tt
    sndf[u][0] = True
    tt += 1
    sndf[u].append(tt)
    for v in M[u]:
        if not sndf[v][0]:
            dfs(v)
    tt += 1
    sndf[u].append(tt)
for i in range(1, n + 1):
    if not sndf[i][0]:
        dfs(i)
for x in sndf[1:]:
    print(*x[1:])

Python: def d(u):
 global t
 C[u]=1;t+=1;D[u]=t
 for v in range(N):
  if M[u][v]and C[v]==0:d(v)
 C[u]=2;t+=1;F[u]=t
N=int(input())
M=[[0]*N for _ in[0]*N]
for e in[list(map(int,input().split()))for _ in[0]*N]:
 for v in e[2:]:M[e[0]-1][v-1]=1
C,D,F=[0]*N,[0]*N,[0]*N
t=0
for i in range(N):
 if C[i]==0:d(i)
for i in range(N):print(i+1,D[i],F[i])