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: from collections import deque
q = deque()

n = int(input())
C = [deque() for _ in range(n+1)]

for i in range(n):
    tmp = list(map(int,input().split()))
    for j in range(tmp[1]):
        C[tmp[0]].append(tmp[2+j])

visited = [False]*(n+1)
d = [0]*(n+1)
f = [0]*(n+1)
t = 0

def stack(i):
    global t
    if visited[i] == False:
        q.append(i)
    while q:
        #ノードの探索開始
        node = q[-1]
        if d[node] == 0:
            t += 1
            d[node] = t
        visited[node] = True
        for _ in range(len(C[node])):
            tmp = C[node].popleft()
            if visited[tmp] == False:
                next_node = tmp
                q.append(next_node)    #未探索の接続ノード
                break
        
        #未探索接続ノードがなければそのノードは探索終了
        else:
            t += 1
            f[q.pop()] = t

for i in range(1,n+1):
    stack(i)

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

Python: from sys import stdin
n = int(stdin.readline())
M = [0] + [list(map(int, stdin.readline().split()[2:])) for i in range(n)]
sndf = [0] + [[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)
    print(*sndf[i][1:])

Python: def curserch(N,k,t,P,n):
    g = 0
    t = t+1
    P[k]["d"] = t
    for i in range(1,n+1):
        if N[k][i]==1 and P[i]["d"]==0:
            P[i]["f"] = g = curserch(N,i,t,P,n)
    if g !=0:
        return g+1
    else:
        return t+1

n = int(input())
A = [[0 for j in range(n+1)] for i in range(n+1)]


for i in range(n):
    vec = input().split()
    u = int(vec[0])
    k = int(vec[1])
    nodes = vec[2:]
    for i in range(int(k)):
        v = int(nodes[i])
        A[u][v] = 1

P=[{"d":0} for i in range(n+1)]
P[1]["f"] = curserch(A,1,0,P,n)
for i in range(1,n+1):
    print(i,P[i]["d"],P[i]["f"])

Python: """Depth First Search."""

n = int(input())

adj = [None]
for i in range(n):
    adj_i = list(map(int, input().split()[2:]))
    adj.append(adj_i)

# searched or not, number of vertex, discovery time and finishing time.
sndf = [None]
for i in range(1, n + 1):
    sndf.append([False, i])
sndf.append(0)

path = []

time = 0

def dfs(u):
    global time
    path.append(u)
    time += 1
    sndf[u].append(time)

    while path:
        u = path[-1]
        if adj[u]:
            v = adj[u].pop(0)
            if not sndf[v][0]:
                sndf[v][0] = True
                time += 1
                sndf[v].append(time)
                path.append(v)
        else:
            path.pop()
            sndf[u][0] = True
            time += 1
            sndf[u].append(time)


for i in range(1, n + 1):
    if not sndf[i][0]:
        dfs(i)

for x in sndf[1:-1]:
    print(*x[1:])

Python: def dfs(G,n):

	global ptr
	
	#探索済
	seen[n] = True

	#行き
	F[n] = ptr
	ptr += 1

	for i in G[n]:
		#次に行けるかを判定
		if seen[i] == True :
			continue
		dfs(G,i)

	#帰り
	L[n] = ptr
	ptr += 1

if __name__ == '__main__':

	n = int(input())
	
	G = [[] for _ in range(n+1)] 
	F = [0 for _ in range(n+1)]
	L = [0 for _ in range(n+1)]

	#深さ優先探索
	#探索済配列
	seen = [False for _ in range(n+1)]

	for i in range(n):
		cmd = list(map(int,input().split()))
		m = cmd[1]
		if m != 0:
			for j in range(m):
				G[i+1].append(cmd[j+2])
	ptr = 1
	for i in range(1,n):
		if seen[i] == False :
			dfs(G,i)

	for i in range(1,n+1):
		print(i,F[i],L[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
d[0]=1
stack+=[1]
check+=[-1]

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

           ## print("stack:",stack)
           ## 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)
            


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

Python: class Node():
    def __init__(self, v):
        self.d = 0
        self.f = 0
        self.v = v

    def __repr__(self):
        return "Node({},{},{})".format(
            self.d, self.f, self.v)


def read_node():
    n = int(input())
    adj_list = [[] for _ in range(n + 1)]

    for _ in range(n):
        id, _, *v = [int(x) for x in input().split()]
        adj_list[id] = Node(v)

    return adj_list


def depth_first_search(adj_list):
    def dfs(id):
        nonlocal adj_list, timestamp

        adj_list[id].d = timestamp
        for adj_id in adj_list[id].v:
            if adj_list[adj_id].d == 0:
                timestamp += 1
                dfs(adj_id)
        timestamp += 1
        adj_list[id].f = timestamp

    timestamp = 1
    for id in range(1, len(adj_list)):
        if adj_list[id].d == 0:
            dfs(id)
            timestamp += 1


def print_result(adj_list):
    for id in range(1, len(adj_list)):
        print(id, adj_list[id].d, adj_list[id].f)


def main():
    adj_list = read_node()
    depth_first_search(adj_list)
    print_result(adj_list)


if __name__ == '__main__':
    main()

Python: n = int(input())
adjacency_list = []
for i in range(n):
    input_list = list(map(int, input().split()))
    adjacency_list.append(input_list[2:])
checked_set = set()
dfs_stack = []
v =[0 for i in range(n)]
f =[0 for i in range(n)]
time = 1
for i in range(n):
    if i not in checked_set:
        dfs_stack = []
        dfs_stack.append(i)
        while dfs_stack:
            current = dfs_stack.pop()
            if current not in checked_set:
                checked_set.add(current)
                v[current] = time
                dfs_stack.append(current)
                for ad in reversed(adjacency_list[current]):
                    if ad-1 not in checked_set:
                        dfs_stack.append(ad-1)
                time +=1
            elif f[current] == 0:
                f[current] = time
                time +=1
for i in range(n):
    print(f'{i+1} {v[i]} {f[i]}')