Go: package main

/*
深さ優先探索
*/

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

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

Python: def dfs(u, node_info, matrix):
    # ????????????????????¨??????????????????
    colors = [0] * len(matrix)
    detect_time = [0] * len(matrix)
    finished_time = [0] * len(matrix)
    time = 1
    stack = list()
    stack.append(u)
    colors[u] = 1
    detect_time[u] = time
    while len(stack):
        for i, val in enumerate(matrix[u]):
            if val == 1 and colors[i] == 0:
                time += 1
                stack.append(i)
                colors[i] = 1
                detect_time[i] = time
                u = i
                break
        else:
            time += 1
            e = stack.pop()
            colors[e] = 2
            finished_time[e] = time
            if len(stack):
                u = stack[-1]
    for i in range(len(matrix)):
        print('{} {} {}'.format(i + 1, detect_time[i], finished_time[i]))


if __name__ == '__main__':
    N = int(input())
    matrix = [[0] * N for _ in range(N)]
    color = [0] * N
    for i in matrix:
        node_info = [int(i) for i in input().split()]
        node_i = node_info[0] - 1
        if not node_info[1] == 0:
            for i in node_info[2:]:
                matrix[node_i][i - 1] = 1
    dfs(0, None, matrix)

Python: def dfs(G, u, t, d, visited):
  found = t
  visited.add(u)
  t += 1
  for v in G[u]:
    if v not in visited:
      t = dfs(G, v, t, d, visited)
  complete = t
  d[u] = (found, complete)
  t+=1
  return t


n = int(input())
G = {}
for _ in range(n):
  entries = list(map(int, input().split(' ')))
  u = entries[0]
  k = entries[1]
  G[u] = set()
  for v in entries[2:]:
    G[u].add(v)

d = {}
visited = set()
t = 1
for i in range(1,n+1):
  if i not in visited:
    t = dfs(G, i, t, d, visited)
for i in sorted(d):
  print(i,d[i][0],d[i][1])

Python: n = int(input())
A = [[0 for i in range(n)] for j in range(n)]

for i in range(n):
    u, k, *v = list(map(int, input().split()))
    for j in v:
        A[int(u)-1][int(j)-1] = 1
        # A[int(j)-1][int(u)-1] = 1

for row in A:
    msg = ' '.join(map(str, row))
    # print(msg)

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

t = 0

# # recursive
# def dfs(u):
#     global t
#     # print('visit:', str(u), str(t))
#     t += 1
#     d[u] = t
#     for i in range(len(A[u])):
#         if A[u][i] == 1 and d[i] == -1:
#             dfs(i)
#     t += 1
#     f[u] = t
            

def get_next(u):
    for i in range(len(A[u])):
        if A[u][i] == 1 and d[i] == -1:
            return i
    return None

def dfs(u):
    global t
    s = []
    s.append(u)
    d[u] = t
    while len(s) > 0:
        p = s[-1]
        v = get_next(p)
        # print(p, 'next:', v)
        # t += 1
        # d[p] = t
        # print('poped:', p)
        
        if v is not None:
            
            if d[v] == -1:
                t += 1
                d[v] = t
                s.append(v)
                # print('[append:', v, 'at', t)
        else:
            t += 1
            # print('complete:', p, 'at', t)
            s.pop()
            f[p] = t


# def dfs(u):
#     s = []
#     t = 0
#     s.append(u)
    
#     while len(s) > 0:
#         p = s.pop()
#         print('init', str(p), d[p], t)
#         if d[p] > -1:
#             print('完了')
#             t += 1
#             f[p] = t
#         else:
#             t += 1
#             d[p] = t
#             print('---visit:', str(p), str(t), 'at', t)
#             has_node = False
#             for i in range(len(A[p])):
#                 if A[p][i] == 1 and d[i] == -1:
#                     print('reserve:', str(i))
#                     has_node = True
#                     s.append(i)
#                     break
#             if not has_node:
#                 t += 1
#                 f[p] = t
#         # print('H_complete:', str(p), str(t))
            


t = 0
for i in range(n):
    if d[i] == -1:
        t += 1
        # print('start from:', str(i))
        dfs(i)


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

Python: def dfs(vertice,connect,went,v_time):
    global time
    for v in connect[vertice]:
        if not went[v]:
            time += 1
            went[v] = time
            dfs(v,connect,went,v_time)
    else:
        time += 1
        v_time[vertice] = time
time = 1
vertices = int(input())
connect = {}
for i in range(vertices):
    temp = input()
    if temp[2] == "0":
        connect[i] = []
    else:
        connect[i] = [int(n) - 1 for n in temp[4:].split(" ")]
went = [0 for n in range(vertices)]
v_time = [0 for n in range(vertices)]
went[0] = time
for i in range(vertices):
    if not v_time[i]:
        dfs(i,connect,went,v_time)
print(went)
print(v_time)

Python: def dfs():
    tt = 0
    for u in range(N):
        if colors[u] == WHITE:
            dfs_visit(u, tt)

def dfs_visit(u, tt):
    tt += 1
    colors[u] = GLAY
    d[u] = tt
    for v in range(N):
        if adjacency_list[u][v] == 1 and colors[v] == WHITE:
            tt = dfs_visit(v, tt)
    tt += 1
    colors[u] = BLACK
    f[u] = tt
    return tt


N = int(input())
adjacency_list = [[0 for j in range(N)] for i in range(N)]
for _ in range(N):
    u, k, *v = map(int, input().split())
    for i in v:
        adjacency_list[u-1][i-1] = 1

WHITE = 0
GLAY = 1
BLACK = 2
colors = [WHITE for _ in range(N)]
d = [0 for _ in range(N)]
f = [0 for _ in range(N)]


dfs()

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