Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

Python: n = int(input())
a = [[] for i in range(n)]

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

d = [0] * n
f = [0] * n
isDiscovered = [False] * n
time_stamp = 0

def dfs(x):
    global time_stamp
    isDiscovered [x] = True
    time_stamp += 1
    d[x] = time_stamp
    for i in a[x]:
        if not isDiscovered[i]:
            dfs(i)
    time_stamp += 1
    f[x] = time_stamp
 
for i in range(n):
    if not isDiscovered[i]:
        dfs(i)
 
for i in range(n):
    print(i+1, d[i], f[i])
 
for i in range(n):
    if not isDiscovered[i]:
        dfs(i)
 
for i in range(n):
    print(i+1, d[i], f[i])

Python: 
# ??±???????????¢?´¢(Depth First Search)

def DFS(i, n):
    for j in range(n):
        if A[i][j] == 1 and d[j] == 0:
            time = time + 1
            d[j] = time
            DFS(j)
    time = time + 1
    f[i] = time

n = int(raw_input())
A = [0] * n
for i in range(n):
    A[i] = [0] * n

for i in range(n):
    value = map(int, raw_input().split())
    u = value[0] - 1
    k = value[1]
    nodes = value[2:]
    for i in range(k):
        v = nodes[i] - 1
        A[u][v] = 1

d = [0] * n
f = [0] * n
time = 1
d[0] = time
DFS(0, n)

for i in range(n):
    print(str(i + 1) + " " + str(d[0]) + " " + str(f[0]))

Python: n=int(input())
#V[u]=[k,[v],d,f]
V=[[0,[],0,0]]
for i in range(n):
    v=[int(i) for i in input().split(" ")]
    u=v.pop(0)
    k=v.pop(0)
    v.sort()
    V.append([k,v,0,0])


def is_finished(Id):
    k=V[Id][0]
    v=V[Id][1]
    for i in range(k):
        if V[v[i]][2]==0:
            return v[i]
    return -1

time=1

while time<=2*n:
 for i in range(1,n+1):
     if V[i][2]==0:
         cur=i
         log=[i]
         break

 while len(log)>0:
    if V[cur][2]==0:
        V[cur][2]=time
        time+=1


    x=is_finished(cur)
    if x!=-1:
        cur=x
        log.append(cur)
    else:
        try:
            log.pop(-1)
            V[cur][3]=time
            time+=1
            if V[cur][3]==V[cur][2]:
                time+=1
                V[cur][3]+=1

            cur=log[-1]
        except:
            pass
for i in range(1,n+1):
    print(i,V[i][2],V[i][3])

Python: def dfs_init(color,n,dq):
	for i in range(n):
		color[i] = "White"

def next(u):
	for v in range(list_next[u],n):
		list_next[u] = v+1
		if list_m[u][v]:
			return v


def dfs_visit(u,color,dq,tt):
	tt = tt
	dq.append(u)
	color[u] = "Gray"
	list_d[u] = tt + 1
	tt += 1
	while dq:
		u = dq[-1]
		v = next(u)
		if v != None:
			if color[v] == "White":
				color[v] = "Gray"
				list_d[v] = tt + 1
				tt += 1
				dq.append(v)
		else:
			dq.pop()
			color[u] = "Black"
			list_f[u] = tt + 1
			tt += 1
	return tt

from collections import deque
n = int(input())
list_m = [[0]*n for i in range(n)]
list_next = [0] * n
list_color = [0] * n
list_d = [0]*n
list_f = [0]*n
dq = deque([])

for i in range(n):
	a,b,*args = map(int, input().split())
	for num in args:
		list_m[a-1][num-1] = 1
tt = 0
list_num = [i+1 for i in range(n)]
dfs_init(list_color,n,dq)
for u in range(n):
	if list_color[u] == "White":
		tt = dfs_visit(u,list_color,dq,tt)

for i in range(n):
	print(list_num[i], list_d[i] ,list_f[i])

Python: def dfs(v, cnt):
    D[v] = cnt
    cnt += 1
    for c in edge[v]:
        if D[c] == -1:
            cnt = dfs(c, cnt)
    F[v] = cnt
    cnt += 1
    return cnt
 
 
V = int(input())
edge = [[] for _ in range(V)]
for _ in range(V):
    u, _, *v = map(lambda x: int(x)-1, input().split())
    edge[u] = sorted(v)
D, F = [-1] * V, [-1] * V
c = 1
for i in range(V):
    if D[i] == -1:
        c = dfs(i, c)
for i, (d, f) in enumerate(zip(D, F)):
    print(i+1, d, f)

Python: def depth_search(i, adj, d, f, t):
    if d[i - 1]:
        return t
    d[i - 1] = t
    t += 1
    for v in adj[i - 1]:
        t = depth_search(v, adj, d, f, t)
    f[i - 1] = t
    t += 1
    return t
n = int(input())
adj = [list(map(int, input().split()))[2:] for _ in range(n)]

d = [0] * n
f = [0] * n

depth_search(1, adj, d, f, 1)

for i, df in enumerate(zip(d, f)):
    print(i, *df)

Python: def DFS(G):
    ans = [0] + [[0,0,0] for _ in range(len(G))]
    def main(G,i):
        ans[0] += 1
        ans[i] = [i, ans[0], ans[0]]
        for j in sorted(G[i-1][2:]):
            if ans[j][0] == 0: main(G,j)
        ans[0] += 1
        ans[i][2] = ans[0]
    for u in G:
        if ans[u[0]][0] == 0: main(G,u[0])
    return ans[1:]


if __name__=='__main__':
    n = int(input())
    G = [list(map(int,input().split())) for _ in range(n)]
    for out in DFS(G): print(*out)

Python: n = int(input())
g = []
for i in range(n):
    a = list(map(int,input().split()))
    g.append(a[2:])
d = [0]*n
f = [0]*n
global t
t = 1
d[0] = 1
x = 1
def find(x):
    global t
    if len(g[x-1]) == 0:
        f[x-1] = t
    for i in g[x-1]:
        if d[i-1] == 0:
            t += 1
            d[i-1] = t
            find(i)
    t += 1
    f[x-1] = t

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