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+1)
	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: from sys import stdin
readline=stdin.readline

#入力
n=int(readline())
m=n+1
u,k,v=[0]*m,[0]*m,[0]*m
for i in range(1,m):
    u[i],k[i],*v[i]=map(int,readline().split())

d=[0]*m
f=[0]*m
flags=[False]*m
t=0
def dfs(now):
    global t
    t+=1
    d[now]=t
    flags[now]=True
    for nex in v[now]:
        if flags[nex]==False:
            dfs(nex)
    t+=1
    f[now]=t
now=1
while True:
    dfs(now)
    for i in range(1,m):
        if flags[i]==False:
            now=i
            break
    else:
        break

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

Python: n=0
t=1
def adjacent_matrix():
    global n
    n=int(input())
    v=[]
    array=[]
    for i in range(n):
        zero=[0 for i in range(n)]
        a=list(map(int,input().split()))
        a=a[2:]
        for j in a:
            zero[j-1]=1
        array.append(zero)
    return array
def dfs(array,i,d,f):
    global t
    if i == n:
        return
    else:
        if(d[i] == 0):
            d[i] = t
            t += 1
            for (j,x) in enumerate(array[i]):
                if x == 1:
                    dfs(array,j,d,f)
            f[i] = t
            t += 1
    return dfs(array,i+1,d,f)


def main():
    array=adjacent_matrix()
    print()
    d=[0 for i in range(n)]
    f=[0 for i in range(n)]
    dfs(array,0,d,f)
    for i in range(n):
        print("{} {} {}".format(i+1,d[i],f[i]))

if __name__ == "__main__":
    main()

Python: #coding:utf-8
from copy import deepcopy

n = int(input())
c = ["white" for i in range(n)]
d = [0 for i in range(n)]
f = [0 for i in range(n)]
S = []
class DFS:
    def __init__(self, key, color="white",nex=None):
        self.color = color
        self.nex = nex
        self.key = key

objListCopy = [DFS(i+1) for i in range(n)]
for i in range(n):
    data = list(map(int,input().split()))
    times = data[1]
    obj = objListCopy[i]
    for j in range(times):
        index = data[2+j] - 1
        nextobj = DFS(index+1)
        obj.nex = nextobj
        obj = obj.nex


time = 1
objList = objListCopy[:]
def check(first,time):
    obj = objList[first]
    c[first] = "gray"
    d[first] = time
    f[first] = time
    S.append(first+1)
    
    while S != []:
        index = S[-1] - 1
        u = objList[index]
        v = u.nex
        
        time += 1
        if v != None and c[v.key - 1] == "white":
            objList[index] = v
            index = v.key - 1
            v = objList[index]
            c[v.key-1] = "gray"
            d[index] = time
            S.append(v.key)

        elif v != None and c[v.key - 1] == "black" and v.nex != None:
            objList[index] = v
            time -= 1
            
        else:
            S.pop()
            c[u.key-1] = "black"
            f[index] = time
    return time


for i in range(n):
    if f[i] == 0:
        objList = deepcopy(objListCopy)
        time = check(i,time) + 1
        

k = 1
for i,j in zip(d,f):
    print(k,i,j)
    k += 1

Python: def solve(v, g, ans, time):
    if ans[v]["found"] != 10**9:
        return time
    time += 1
    # print(v + 1, time, file=sys.stderr)
    ans[v]["found"] = time
    for a in g[v]:
        time = solve(a, g, ans, time)
    time += 1
    # print(v + 1, time, file=sys.stderr)
    ans[v]["complete"] = time
    return time


def resolve():
    n = int(input())
    V = [list(map(int, input().split())) for _ in range(n)]
    g = [[] for _ in range(n)]
    for v, k, *a in V:
        v -= 1
        for ai in a:
            ai -= 1
            g[v].append(ai)
    ans = [{"found": 10**9, "complete": -1} for _ in range(n)]
    time = solve(0, g, ans, 0)
    for i in range(n):
        if ans[i]["found"] == 10**9:
            solve(i, g, ans, time)
        print(i + 1, ans[i]["found"], ans[i]["complete"])


resolve()

Python: def dfs_visit(u):
    global dfs_color, d, f, t
    color[u] = GRAY
    d[u] += t
    t += 1
    for v in range(n):
        if M[u][v] == 0:
            continue
        if color[v] == WHITE:
            dfs_visit(v)
    color[u] = BLACK
    f[u] += t
    t += 1

n = int(input())
M = [[False for i in range(n)] for j in range(n)]
WHITE = 0
GRAY = 1
BLACK = 2
color = [WHITE for i in range(n)]
d = [0 for i in range(n)]
f = [0 for i in range(n)]
t = 1
for i in range(n):
        a = list(map(int, input().split()))
        for j in range(a[1]):
            M[a[0] - 1][a[j + 2] - 1] = True
for u in range(n):
    if color[u] == WHITE:
        dfs_visit(u)
for u in range(n):
    print(str(u + 1), str(d[u]), str(f[u]), sep = " ")