Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

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

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	ans := make([][2]int, N)
	time := 0
	found := make(map[int]bool)
	var dfs func(cur int)
	dfs = func(cur int) {
		time++
		ans[cur][0] = time
		found[cur] = true
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if !found[next] {
				dfs(G[cur][i])
			}
		}
		time++
		ans[cur][1] = time
	}
	for i := 0; i < N; i++ {
		if !found[i] {
			dfs(i)
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprint(wtr, i+1)
		for j := 0; j < 2; j++ {
			fmt.Fprint(wtr, " ")
			fmt.Fprint(wtr, ans[i][j])
		}
		fmt.Fprintln(wtr)
	}
	wtr.Flush()
}

Python: def visit(u):
    global color, d, f, t
    color[u] = GRAY
    d[u] += t
    t += 1
    for v in range(n):
        if (M[u][v] == 0):
            continue
        else:
            if (color[v] == WHITE):
                visit(v)
    color[u] = BLACK
    f[u] = t
    t += 1

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

WHITE = 0
GRAY = 1
BLACK = 2
color = [WHITE for i in range(n)]
d, f = [0 for i in range(n)]
t = 1
for u in range(n):
    if (color[u] == WHITE):
        visit(u)
for u in range(n):
    print(str(u+1), str(d[u]), str(f[u]), sep = " ")

Python: #深さ優先探索
import sys
input = sys.stdin.readline
from collections import deque

#グラフ作成(無向グラフでは#を消す)
N = int(input())
graph = [deque([]) for _ in range(N+1)]
for _ in range(N):
    u, k, *v = [int(x) for x in input().split()]
    v.sort()
    for i in v:
        graph[u].append(i)
        #graph[i].append(u)
        
time = 0
arrive_time = [-1] * (N+1) #到着時刻
finish_time = [-1] * (N+1) #終了時刻

def dfs(v):
    global time
    time += 1
    stack = [v]
    arrive_time[v] = time
    while stack:
        v = stack[-1]
        if graph[v]:
            w = graph[v].popleft()
            if arrive_time[w] < 0:
                time += 1
                arrive_time[w] = time
                stack.append(w)
        else:
            time += 1
            finish_time[v] = time
            stack.pop()
    return [arrive_time, finish_time]


# 孤立している頂点対策
for i in range(N):
    if arrive_time[i+1] < 0:
        ans = dfs(i+1)

# 頂点番号、発見時刻、完了時刻
for i in range(N):
    temp = [i + 1, ans[0][i+1], ans[1][i+1]]
    print(* temp)

Python: def main():
    """有向グラフの深さ優先探索
    
    Note: V[i]は頂点iから通じる頂点の集合を意味するが, 
             V[i]: {i}とV[i]: Noneは同値とされている。
    """
    stack = []
    passed_lines = []
    
    n = int(input())
    V = [None]*(n+1)
    D = [None]*(n+1)
    F = [None]*(n+1)
    passed_vertices = set()
    vertices = set(range(1, n+1))
    
    for i in range(1, n+1):
        _, _, *v = map(int, input().split())
        V[i] = set(v)

    i = 1
    time = 1
    stack.append(i)
    passed_vertices.add(i)
    D[i] = time
    while i <= n:
        new_vertices = list(V[i] - passed_vertices - {i})
        new_vertices.sort()
        if new_vertices:
            i = new_vertices[0]
            stack.append(i)
            time += 1
            if D[i] is None:
                D[i] = time
                passed_vertices.add(i)
            continue
        else:
            while stack:
                i = stack.pop()
                time += 1
                if list(V[i] - passed_vertices - {i}):
                    stack.append(i)
                    time -= 1
                    break
                if F[i] is None: 
                    F[i] = time
        if not list(V[i] - passed_vertices - {i}) and not stack:
            rest_vertices = list(vertices-passed_vertices)
            if rest_vertices:
                i = min(rest_vertices)
                stack.append(i)
                time += 1
                if D[i] is None:
                    D[i] = time
                    passed_vertices.add(i)
            else:
                break
    for id, d, f in zip(range(1, n+1), D[1:], F[1:]):
        print("{} {} {}".format(id, d, f))
        
if __name__ == "__main__":
    main()

Python: #coding:utf-8
        
def DFS(i,A,d,f,t):
    if d[i-1]:
        return t
    d[i-1]=t
    t+=1
    for j in A[i-1]:
        t=DFS(j,A,d,f,t)
    f[i-1]=t
    t+=1
    return t

if __name__=="__main__":
    n=int(input())
    A=[]
    for i in range(n):
        A.append(list(map(int,input().split(" ")))[2:])
    d=[0]*n
    f=[0]*n
    t=1
    for i in range(n):
        if d[i]==0:
            t=DFS(i+1,A,d,f,t)
    for i in range(n):
        print("{} {} {}".format(i+1,d[i],f[i]))

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

Python: n = int(input())
a = [None]
for i in range(n):
    adj = list(map(int,input().split()))
    a.append(adj[2:])
    
s = [None]
for i in range(1, n + 1):
    s.append([False, i])
    
time = 0

def dfs(u):
    global time
    s[u][0] = True
    time += 1
    s[u].append(time)
    
    for v in a[u]:
        if s[v][0] == False:
            dfs(v)
            
    time += 1
    s[u].append(time)
    
for i in range(1,n+1):
    if s[i][0] == False:
        dfs(i)
        
for x in s[1:]:
    print(*x[1:])