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: from collections import deque
n = int(input())
data = [None]*n
unvisited = [1]*n
for _ in range(n):
    a,*b = map(int,input().split())
    a -= 1
    data[a] = deque([i-1 for i in b[1:]])

d = [-1]*n
f = [-1]*n
t = 0

dq = deque([])
for u in range(n):
    if unvisited[u]:
        dq.append(u)
        unvisited[u] = 0
        t += 1
        d[u] = t
        while dq:
            k = dq[-1]
            if data[k]:
                v = data[k].popleft()
                if unvisited[v]:
                    unvisited[v] = 0
                    t += 1
                    d[v] = t
                    dq.append(v)
            else:
                dq.pop()
                t += 1
                f[k] = t

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

Python: def dfs(i):
    global t
    t += 1
    D[i] = t
    for e in es[i]:
        if D[e] == 0:
            dfs(e)
    t += 1
    F[i] = t


if __name__ == "__main__":
    N = int(input())
    es = [[] for _ in range(N+1)]
    for _ in range(N):
        ipts = [int(ipt) for ipt in input().split()]
        if ipts[1] > 0:
            es[ipts[0]] = ipts[2:]
    D = [0 for _ in range(N+1)]
    F = [0 for _ in range(N+1)]
    t = 0
    for i in range(1, N+1):
        if D[i] == 0:
            dfs(i)
    for i in range(1, N+1):
        print(i, D[i], F[i])

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

WHITE = 0
GRAY = 1
BLACK = 2
color, d, f = [WHITE for i in range(n)]
t = 1

def visit(u):
    color[u] = GRAY
    d[u] += t
    t += 1
    for v in range(n):
        if (M[u-1][v-1] == 0):
            continue
        if (color[v] == WHITE):
            visit(v)
    color[u] = BLACK
    f[u] = t
    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: 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 j in range(tmp[1]):
        M[tmp[0]-1][tmp[j+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: import sys
n = int(input())
input_line = [[int(i) for i in str.split()] for str in sys.stdin.read().splitlines()]
for i in range(n):
    input_line[i] = [] if len(input_line[i]) == 2 else input_line[i][2:]
detect_time = [1] * n
finish_time = [0] * n
is_visit = [False] * n
stack = [1]
time = 1

while(len(stack) != 0):
    time += 1
    now = stack[-1] - 1
    if len(input_line[now]) == 0:
        finish_time[stack.pop()-1] = time
    else:
        detect = input_line[now].pop(0)
        if is_visit[detect-1]:
            finish_time[stack.pop()-1] = time
            continue
        stack.append(detect)
        detect_time[detect-1] = time
        is_visit[detect-1] = True

for id in range(n):
    print('{0} {1} {2}'.format(id+1, detect_time[id], finish_time[id]))

Python: from collections import deque
n = int(input())
graph = [deque([]) for _ in range(n+1)]
ans = [[i, ] for i in range(n+1)]
for i in range(n):
  u, k, *v = list(map(int, input().split()))
  for j in v:
    graph[u].append(j)
stack = deque()
stack.append(1)
marked = []
t = 0
def dfs(v):
  global t
  marked.append(v)
  t += 1
  ans[v].append(t)
  for i in graph[v]:
    if i in marked:
      continue
    else:
      marked.append(i)
      dfs(i)
  t += 1
  ans[v].append(t)
for i in range(1, n+1):
  if len(ans[i])==1:
    dfs(i)
for i, x in enumerate(ans):
  if i==0:
    continue
  print(*x)

Python: from collections import Counter
import sys

def input():
    return sys.stdin.readline().strip()

def dfs(v):
    start[v] = lb()
    for w in g[v]:
        if start[w] != None:
            continue
        dfs(w)
    end[v] = lb()

n = int(input())
g = [None] * (n+1)
start = [None] * (n+1)
end = [None] * (n+1)
lb = iter(range(1,2*n+1)).__next__
for _ in range(n):
    u,k,*vk = map(int,input().split())
    g[u] = vk
for v in range(1,n+1):
    if start[v] != None:
        continue
    dfs(v)

for i in range(1,n+1):
    print(i,start[i],end[i])

Python: n = int(input())
G = [[] for _ in range(n)]
for _ in range(n):
    u, k, *v = map(int, input().split())
    u -= 1
    G[u].extend(v)
seen = [False] * n
d = [-1] * n
f = [-1] * n
t = 1

def dfs(v):
    global t
#     print(v+1, t)
    d[v] = t
    t += 1
    seen[v] = True
    for next_v in G[v]:
        next_v -= 1
        if not seen[next_v]:
            t = dfs(next_v)
    f[v] = t
    t += 1
    return t

def main():
#     todo = []
#     seen[0] = True
    for i in range(n):
        if not seen[i]:
            dfs(i)
    for i in range(n):
        print(i+1, d[i], f[i])
#     print(G)

if __name__ == "__main__":
    main()