Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N+1)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

Python: N=int(input())
L=[[10**9]for i in range(N+1)]
for i in range(N):
    l=list(map(int,input().split()))
    for j in range(l[1]):
        L[i+1].append(l[2+j])
#print(L)
for i in range(N+1):
    L[i].sort(reverse=True)
    
#print(L)
ans=[]
for i in range(N+1):
    ans.append([0,0])


from collections import deque 

Q=deque()
cnt=1
for i in range(N):
    Q.append([0,N-i])
for i in range(10**7):

    if len(Q)==0:
        break
    q0,q1=Q.pop()
    #print(q0,q1)
    if q1!=10**9:
        if ans[q1][0]==0:
            ans[q1][0]=cnt
            cnt+=1
            for j in L[q1]:
                Q.append([q1,j])
    else:
        ans[q0][1]=cnt
        cnt+=1
    #print(ans,Q)
for i in range(1,N+1):
    print(i,ans[i][0],ans[i][1])

Python: from sys import stdin
from collections import deque

def read_graph(n):
    A = [ [0]*(n+1) for _ in range(n+1) ]
    for _ in range(n):
        line = deque(stdin.readline().strip().split())
        i = line.popleft()
        line.popleft()
        for k in line:
            A[int(i)][int(k)] = 1
    return A

def dfs_ctrl(n, A):
    color = ["WHITE"] * (n+1)
    d = [0] * (n+1)
    f = [0] * (n+1)
    time = 0

    def dfs(u):
        nonlocal color
        nonlocal time
        if color[u] == "WHITE":
            color[u] = "GRAY"
            time += 1
            d[u] = time

            for v in range(1, n+1):
                if A[u][v] and color[v] == "WHITE":
                    dfs(v)
            color[u] = "BLACK"
            time += 1
            f[u] = time

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

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

n = int(input())
A = read_graph(n)
dfs_ctrl(n, A)

Python: n=int(input())
a=[[0 for i in range(n)]for j in range(n)]
for i in range(n):
    v=list(input().split())
    for j in range(len(v)):
        v[j]=int(v[j])
    x=2
    for k in range(v[1]):
        a[i][v[x+k]-1]=1
#print(a)

stack=[]
v=[]
d=[0]*n
f=[0]*n
t=1

while len(v)<n:
    for i in range(n):
        if i+1 not in v:
            stack.append(i+1)
            d[i]=t
            break
        else: pass
        
    while len(stack)!=0:
        for i in range(n):
            if a[stack[-1]-1][i]==1 and stack[-1]-1!=i and i+1 not in v:
                stack.append(i+1)
                a[stack[-1]-1][i]==0
                t+=1
                d[i]=t
            elif i==n-1:
                t+=1
                f[stack[-1]-1]=t
                v.append(stack.pop())
            else: pass
            # print("stack ",stack)
            #print("v ",v)
#print("d=",d," f=",f)
for i in range(n):
    print(i+1,d[i],f[i])

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

import sys

UNVISITED, VISITED_IN_STACK, POPPED_OUT = "BEFORE", "IN", "AFTER"


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(v_init):
    global time
    # init the first node of overall graph iterations(times >= 1)
    vertex_visit_stack.append(v_init)
    vertex_status_list[v_init] = VISITED_IN_STACK
    vertex_d_time[v_init] += time
    # init end
    while len(vertex_visit_stack) > 1:
        time += 1
        current_vertex = vertex_visit_stack[-1]
        next_vertex = get_next_vertex(node=current_vertex)
        # print(current_vertex, next_vertex, vertex_status_list, vertex_visit_stack)
        if next_vertex and vertex_status_list[next_vertex] is UNVISITED:
            vertex_status_list[next_vertex] = VISITED_IN_STACK
            vertex_d_time[next_vertex] += time
            vertex_visit_stack.append(next_vertex)

        else:
            other_vertex = get_next_vertex(current_vertex)
            if other_vertex:
                graph_dfs(other_vertex)
            else:
                vertex_visit_stack.pop()
                vertex_status_list[current_vertex] = POPPED_OUT
                vertex_f_time[current_vertex] += time

    return None


def get_next_vertex(node):
    for j in range(vertex_num):
        if adj_matrix[int(node) - 1][j]:
            adj_matrix[int(node) - 1][j] = 0
            return j + 1


def dfs_start():
    global time
    for i in range(vertex_num):
        if vertex_status_list[i + 1] == UNVISITED:
            # print('round', i + 1)
            graph_dfs(v_init=i + 1)
            time += 1


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_status_list = [UNVISITED] * vertex_num
    vertex_status_list.insert(0, 'NULL')
    vertex_d_time, vertex_f_time = [[0] * (vertex_num + 1) for _ in range(2)]
    adj_matrix = generate_adj(vertex_info)

    time = 1
    dfs_start()

    for k in range(vertex_num):
        print(k + 1, vertex_d_time[k + 1], vertex_f_time[k + 1])