Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	timer := 1
	startNode := 1
	for {
		visit(startNode, &timer, childrenMap, timeRecordMap)
		startNode = findStartNode(childrenMap, timeRecordMap)
		if startNode < 0 {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	return x
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

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

import sys

WHITE, GRAY, BLACK = 0, 1, 2


def generate_adj(v_info):
    for v_detail in v_info:
        v_adj_list = v_detail[2:]
        assert len(v_adj_list) == int(v_detail[1])
        for each in v_adj_list:
            init_adj_matrix[int(v_detail[0]) - 1][int(each) - 1] = 1
    return init_adj_matrix


def graph_dfs(start_node_index):
    # init the first node
    v_index = int(start_node_index)
    vertex_visit_stack.append(v_index)
    vertex_color_list[v_index] = GRAY
    time = 1
    vertex_d_time[v_index] += time
    # init end
    while len(vertex_visit_stack) > 1:
        current_vertex = vertex_visit_stack[-1]
        try:
            next_vertex = adj_matrix[current_vertex - 1].index(1) + 1
        except ValueError:
            # print('err')
            vertex_visit_stack.pop()
            vertex_color_list[current_vertex] = BLACK
            time += 1
            vertex_f_time[current_vertex] += time
        else:
            if vertex_color_list[next_vertex] == WHITE:
                # print('w2g', current_vertex, next_vertex, vertex_color_list[next_vertex])
                vertex_color_list[next_vertex] = GRAY
                time += 1
                vertex_d_time[next_vertex] += time
                vertex_visit_stack.append(next_vertex)
                # node A to B only visit once
                adj_matrix[current_vertex - 1][next_vertex - 1] = 0
            else:
                time += 1
                vertex_f_time[current_vertex] += time
                vertex_visit_stack.pop()
    return None


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertex_num = int(_input[0])
    vertex_info = list(map(lambda x: x.split(), _input[1:]))
    init_adj_matrix = [[0] * vertex_num for _ in range(vertex_num)]
    # assert len(vertex_info) == vertex_num

    vertex_visit_stack = [-1]
    vertex_color_list = [WHITE] * (vertex_num + 1)
    vertex_d_time, vertex_f_time = [0] * (vertex_num + 1), [0] * (vertex_num + 1)
    adj_matrix = generate_adj(vertex_info)

    graph_dfs(start_node_index=1)
    for i in range(vertex_num):
        print(i + 1, vertex_d_time[i + 1], vertex_f_time[i + 1])

Python: from sys import stdin
n = int(stdin.readline())
M = [None]
M += [list(map(int, stdin.readline().split()[2:])) for i in range(n)]
sndf = [None]
sndf += [[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: n=0
t=2
def adjacent_matrix():
    global n
    n=int(input())
    v=[]
    array=[]
    for i in range(n):
        zero=[0 for i in range(n)]
        a=list(map(int,input().split()))
        a=a[2:]
        for j in a:
            zero[j-1]=1
        array.append(zero)
    return array
def dfs(array,i,d,f):
    global t
    if i == n:
        return
    else:
        if(d[i] == 0):
            for (j,x) in enumerate(array[i]):
                if x == 1:
                    d[j] = t
                    t += 1
                    dfs(array,j,d,f)
            f[i] = t
            t += 1
    return dfs(array,i+1,d,f)


def main():
    array=adjacent_matrix()
    print()
    d=[0 for i in range(n)]
    f=[0 for i in range(n)]
    d[0]=1
    f[0]=1
    dfs(array,0,d,f)
    for i in range(n):
        print("{} {} {}".format(i+1,d[i],f[i]))

if __name__ == "__main__":
    main()

Python: n = int(raw_input())

d = [0 for i in range(n)]
f = [0 for i in range(n)]
a = [[0 for i in range(n)] for j in range(n)]
st = [0 for i in range(n)]
time = [0]

def dfs_visit(s):
    st[s] = 1
    time[0] += 1
    d[s] = time[0]
    
    for k in range(n):  
      if a[s][k] == 1 and st[k] == 0:
          dfs_visit(k)
    time[0] += 1
    f[s] = time[0]

def main():
    for s in range(n):
        if st[s] == 0:
            def_visit(s)
    for s in range(n):
        print(s+1,d[s],f[s])

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])