Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

Python: n = int(input())
graph = [[0 for i in range(n)] for j in range(n)]
d = [0] * n
f = [0] * n
g = [0] * n

time = 0

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

def search(i):
    global time
    time = time + 1
    d[i] = time
    g[i] = 1
    for j in range(n):
        if (graph[i][j] == 1) & (g[j] == 0):
            search(j)
    time = time + 1
    f[i] = time

for i in range(n):
    if g[i] == 0:
        search(i)
[print(i+1, d[i], f[i]) for i in range(n)]

Python: import sys


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


def dfs(c, n, G, ans):
    count = c
    for i, flag in enumerate(G[n]):
        if flag == 1 and ans[i][0] == 0:
            count += 1
            ans[i][0] = i + 1
            ans[i][1] = count
            ans[i][2] = dfs(count, i, G, ans)
            count = ans[i][2]
    else:
        return count + 1


def main():
    n = int(input())
    G = [[0] * n for _ in range(n)]
    ans = [[0] * 3 for _ in range(n)]
    for i in range(n):
        u, k, *v = map(int, input().split())
        for j in range(k):
            G[u-1][v[j]-1] = 1

    count = 1
    for i in range(n):
        if ans[i][0] == 0:
            ans[i][0] = i + 1
            ans[i][1] = count
            ans[i][2] = dfs(count, i, G, ans)
            count = ans[i][2] + 1

    for i in range(n):
        print(*ans[i])


if __name__ == '__main__':
    main()

Python: from collections import deque

n = int(input())

g = [deque([]) *n for _ in range(n)]

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

time = 0
arrive_time = [-1] * n
finish_time = [-1] * n
def dfs(v):
    global time
    time += 1
    stack = [v]
    arrive_time[v] = time
    while stack:
        v = stack[-1]
        if g[v]:
            w = g[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]

for i in range(n):
    if arrive_time[i] < 0:
        ans = dfs(i)

for j in range(n):
    temp = [j+1, ans[0][j], ans[1][j]]
    print(*temp)

Python: N = int(input())
adj_list = []
for _ in range(N):
    line = list(input().split(" "))
    adj_list.append([int(k) - 1 for k in line[2:]])

d = [-1 for _ in range(N)]
f = [-1 for _ in range(N)]
time = 1

visited = set()

def dfs(p):
    global time
    if p in visited:
        return

    d[p] = time
    time += 1
    visited.add(p)
    for ad in adj_list[p]:
        if ad not in visited:
            dfs(ad)
    f[p] = time
    time += 1

for i in range(N):
    dfs(i)

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

Python: # coding: utf-8
# Your code here!

n = int(input())
M = []
for i in range(n):
    adj = list(map(int,input().split()))
    if adj[1] == 0:
        M += [[]]
    else:
        M += [adj[2:]]
time = 1
ans = [[j+1,0,0] for j in range(n)] # id d f

while True:
    for i in range(n):
        if ans[i][1] == 0:
            stack = [i]
            ans[i][1] = time
            time += 1
            break
        elif i == n-1:
            for k in range(n):
                print(*ans[k])
            exit()
    while stack != []:
        u = stack[-1]
        if M[u] != []:
            for i in range(len(M[u])):
                v = M[u][0]
                M[u].remove(v)
                if ans[v-1][1] == 0:
                    ans[v-1][1] = time
                    stack.append(v-1)
                    time += 1
                    break
        else:
            stack.pop()
            ans[u][2] = time
            time += 1

Python: n=int(input())
G=[]
for i in range(n):
    L=list(map(int,input().split()))
    G.append(L[2:])
    for j in range(len(G[-1])):
        G[-1][j]-=1

Forder=[-1]*n
Lorder=[-1]*n
ptr=1
def dfs(v):
    #print(v)
    #print(G[v])
    #print()
    global ptr

    Forder[v]=ptr
    ptr+=1

    for next in G[v]:
        if Forder[next]!=-1:
            continue
        dfs(next)
    
    Lorder[v]=ptr
    ptr+=1

#while True:
#    #print(Forder,Lorder)
#    for i in range(n):
#        if Forder[i]!=-1 and Lorder[i]!=-1:
#            pass
#        else:
#            dfs(i)
#            continue
#
#        if i==n-1:
#            break
#    else:
#        continue
#    break
#
#for i in range(n):
#    print(i+1,Forder[i],Lorder[i])

##########
for i in range(n):
    if Forder[i]==-1 or Lorder[i]==-1:
        dfs(i)

for i in range(n):
    print(i+1,Forder[i],Lorder[i])

Python: n = int(input())
Adj = [[0 for i in range(n)] for i in range(n)]
 
for i in range(n):
    u = list(map(int, input().split()))
    if u[1] > 0:
        for i in u[2: 2 + u[1]]:
            Adj[u[0] - 1][i - 1] = 1
 
color = [0] * n
d = [0] * n
f = [0] * n
time = 0
def dfs(u):
    global time
    color[u - 1] = 1
    time += 1
    d[u - 1] = time
    for i in range(1, n+1):
        if Adj[u - 1][i - 1] == 1 and color[i - 1] == 0:
            dfs(i)
    color[u - 1] = 2
    time += 1
    f[u - 1] = time

for i in range(1, n+1):
    if color[i-1] == 0:
        dfs(i)
for i in range(n):
    print("{} {} {}".format(i+1,d[i],f[i]))