Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

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

"""

input:
6
1 2 2 3
2 2 3 4
3 1 5
4 1 6
5 1 6
6 0

output:
1 1 12
2 2 11
3 3 8
4 9 10
5 4 7
6 5 6

"""
import sys

UNVISITED, VISITED_IN_STACK, POPPED_OUT = 0, 1, 2


def dfs(v_init):
    global timer

    # init the first node of overall graph iterations(times >= 1)
    stack = list()
    stack.append(v_init)
    d_time[v_init] += timer
    # init end

    while stack:
        current = stack[-1]
        v_table = adj_table[current]
        visited[current] = VISITED_IN_STACK
        # if adj is None, current's adj(s) have been all visited
        adj = v_table.pop() if v_table else None

        if adj:
            if visited[adj] is UNVISITED:
                visited[adj] = VISITED_IN_STACK
                timer += 1
                d_time[adj] += timer
                stack.append(adj)
        else:
            stack.pop()
            visited[current] = POPPED_OUT
            timer += 1
            f_time[current] += timer

    return None


def dfs_init():
    global timer
    for v in range(v_num):
        if visited[v + 1] == UNVISITED:
            timer += 1
            dfs(v + 1)


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    v_num = int(_input[0])
    vertices = map(lambda x: x.split(), _input[1:])

    # config length = (v_num + 1)
    # stack = []
    visited = [UNVISITED] * (v_num + 1)
    d_time, f_time = ([0] * (v_num + 1) for _ in range(2))
    adj_table = tuple([] for _ in range(v_num + 1))
    for v_info in vertices:
        v_index, adj_num, *adj_list = map(int, v_info)
        # assert len(adj_list) == adj_num
        adj_table[v_index].extend(sorted(adj_list, reverse=True))

    # timing start from 1
    timer = 0
    dfs_init()

    for index, time_info in enumerate(zip(d_time[1:], f_time[1:]), 1):
        print(index, *time_info)

Python: n = int(input())
Adj = [[0 for i in range(n)] for i in range(n)]
 
for i in range(n):
    u = list(map(int, input().split()))
    if u[1] > 0:
        for i in u[2: 2 + u[1]]:
            Adj[u[0] - 1][i - 1] = 1
 
color = [0] * n
d = [0] * n
f = [0] * n
time = 0
def dfs(u):
    global time
    color[u - 1] = 1
    time += 1
    d[u - 1] = time
    for i in range(n):
        if Adj[u - 1][i] and color[i] == 0:
            dfs(i + 1)
    color[u - 1] = 2
    time += 1
    f[u - 1] = time

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

Python: # -*- coding: utf-8 -*-


class Graph:
    def __init__(self, n, adj_matrix):
        self.n = n
        self.g = adj_matrix

    def show(self):
        for _ in self.g:
            print(*_)

    def dfs(self, u, init=False):
        if init:
            self.states = [1] * self.n
            self.stack = []
            self.d = [None] * self.n
            self.f = [None] * self.n
            self.time = 0

        self.states[u] = 0
        self.time += 1
        self.d[u] = self.time

        for v, edge in enumerate(self.g[u]):
            if edge and self.states[v]:
                self.dfs(v)

        self.states[u] = 0
        self.time += 1
        self.f[u] = self.time

    def show_dfs(self, start=0):
        self.dfs(u=start, init=True)
        for i, (d, f) in enumerate(zip(self.d, self.f)):
            print(i + 1, d, f)


if __name__ == '__main__':
    n = int(input())
    adj_matrix = [[0] * n for i in range(n)]
    for i in range(n):
        for v in input().split()[2:]:
            adj_matrix[i][int(v) - 1] = 1

    g = Graph(n, adj_matrix)
    g.show_dfs()

Python: def srch(u, cnt, Dst, Fst, Lst):
    S = [u]
    Fst[u] = cnt
    while(len(S) > 0):
        cnt += 1
        u = S.pop()
        if Dst[u] is not None and len(Dst[u]) > 0:
            while(len(Dst[u])):
                u1 = Dst[u].pop()
                if Fst[u1] == 0:
                    S.append(u)
                    S.append(u1)
                    Fst[u1] = cnt
                    break
                else:
                    Lst[u] = cnt
        else:
            Lst[u] = cnt
    return cnt + 1

def main():
    num = int(input())
    Dst = [None for i in range(num + 1)]
    Fst = [0] * (num + 1)
    Lst = Fst[:]

    for n in range(1, num+1):
        a = list(map(int,input().split()))
        u = a[0]
        if a[1] > 0:
            Dst[u] = a[2:]
            Dst[u].reverse()

    cnt = 1
    for i in range(1,num):
        if Fst[i] == 0:
            cnt = srch(i, cnt, Dst, Fst, Lst)

    for n in range(1, num+1):
        print("{} {} {}".format(n,Fst[n],Lst[n]))

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)
    print(*sndf[i][1:])

Python: def main():
    n=int(input())
    u,k,v=0,0,[[] for _ in range(n+1)]
    for i in range(n):
        l=list(map(int,input().split()))
        u=l[0]
        for j in l[2:]:
            v[u].append(j)
    d=[0]*(n+1)
    f=[0]*(n+1)

    def dfs(s,t):
        d[s]=t
        for i in v[s]:
            if d[i]==0:
                t=dfs(i,t+1)
        f[s]=t+1
        return t+1

    s,t=1,1
    while 0 in d[1:]:
        T=dfs(s,t)
        for i in range(1,n+1):
            if d[i]==0:
                s=i
                t=T+1
                break

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

if __name__ == '__main__':
    main()