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())
G = [[] for _ in range(n)]
u1 = 0
for _ in range(n):
    u, k, *v = [int(i) for i in input().split()]
    G[u - 1] = v
    if k != 0 and u1 == 0:
        u1 = u

time = 1
u = u1
D = []
F = []
out = [[i+1, 0, 0] for i in range(n)]
T = []
while True:
    if u not in D:
        out[u - 1][1] = time
        D.append(u)
        T.append(u)

    for f in F:
        if f in G[u - 1]:
            idx = G[u - 1].index(f)
            del G[u - 1][idx]

    if G[u - 1] == []:
        time += 1
        out[T.pop() - 1][2] = time
        F.append(u)
        if T == []:
            if len(D) == n:
                break
            else:
                for ni in range(n):
                    if ni + 1 not in D:
                        u = ni + 1
                        break
                time += 1
                continue
        else:
            u = T[-1]
    else:
        if G[u - 1][0] != u:
            time += 1
        u = G[u - 1].pop(0)

for ni in range(n):
    print(*out[ni])

Python: from collections import deque


def dfs(root):
    time = 1
    stack.append(root)
    color[root] = 'gray'
    arrive[root] = time
    time += 1

    while len(stack) > 0:
        node = stack[-1]
        for next in range(n):
            if adjMat[node][next] == 1:
                if color[next] == 'white':
                    color[next] = 'gray'
                    arrive[next] = time
                    time += 1
                    stack.append(next)
                    break
        # In case there in no adjacent node whose color is white
        color[node] = 'black'
        finish[node] = time
        time += 1
        stack.pop()


n = int(input())

adjMat = [[0] * n for _ in range(n)]
color = ['white'] * n
stack = deque()
arrive = [0] * n
finish = [0] * n

for _ in range(n):
    adj = list(map(int, input().split()))
    i = adj[0]
    v = adj[2:]
    for j in v:
        adjMat[i - 1][j - 1] = 1

dfs(0)

for i in range(n):
    out = ''
    out += '{} {} {}'.format(i+1, arrive[i], finish[i])
    print(out)

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-1][v-1] == 0):
            continue
        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):
    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
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 main():
    import sys
    N = int(sys.stdin.readline())
    L1 = [list(map(int, sys.stdin.readline().split())) for _ in range(N)]
    #print(L1)
    edge = [[] for _ in range(N+1)]
    for row in L1:
        for ele in row[2:]:
            edge[row[0]].append(ele)
            #edge[ele].append(row[0])

    #print(edge)
    sys.setrecursionlimit(1000)
    
    go = [-1 for _ in range(N+1)]
    go[0], go[1] =0, 1
    back = [-1 for _ in range(N+1)]
    
    d = [1]
    def dfs(p):
        if edge[p]:
            for c in edge[p]:
                if go[c]==-1:
                    d[0]+=1
                    go[c] = d[0]
                    dfs(c)
        
        #抜ける順
        d[0]+=1
        back[p] =d[0]
                
    dfs(1)
    for i in range(2, N+1):
        if go[i] ==-1:
            d[0]+=1
            go[i] = d[0]
            dfs(i)
    for i in range(1, N+1):
        print(i, go[i], back[i])




if __name__=='__main__':
    main()