Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	ans := make([][2]int, N)
	time := 0
	found := make(map[int]bool)
	var dfs func(cur int)
	dfs = func(cur int) {
		time++
		ans[cur][0] = time
		found[cur] = true
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if !found[next] {
				dfs(G[cur][i])
			}
		}
		time++
		ans[cur][1] = time
	}
	for i := 0; i < N; i++ {
		if !found[i] {
			dfs(i)
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprint(wtr, i+1)
		for j := 0; j < 2; j++ {
			fmt.Fprint(wtr, " ")
			fmt.Fprint(wtr, ans[i][j])
		}
		fmt.Fprintln(wtr)
	}
	wtr.Flush()
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); ++i)
using namespace std;

int G[100][100];
int d[100] = {0};
int f[100];
int now_time = 1;
stack<int> search_stack;

int main() {
    // 制約見て！！！デカかったらlong longにすること！
    int n, u, k, v;
    cin >> n;
    rep(i, n) {
        cin >> u >> k;
        u--;
        rep(j, k) {
            cin >> v;
            v--;
            G[u][v] = 1;
        }
    }
    rep(i,n){
        if(d[i]==0){
            search_stack.push(i);
            d[i]=now_time++;
        }
        while(search_stack.size() > 0) {
            int s = search_stack.top();
            rep(i, n + 1) {
                if(i == n) {
                    f[s] = now_time++;
                    search_stack.pop();
                }
                else if(s != i && d[i] == 0 && G[s][i] == 1) {
                    search_stack.push(i);
                    d[i] = now_time++; 
                    break;
                }
            }
        }
    }
    rep(i, n) { printf("%d %d %d\n", i + 1, d[i], f[i]); }
}

C++: #include <iostream>
#include <vector>
#include <list>
#include <cstdlib>

const int MAX_N = 100;

struct Node {
  int v;
  int firstVisitedTime;
  int lastVisitedTime;
  bool visited;
};

void visit(int *count, int n, std::vector<std::list<int> *> *graph, std::vector<struct Node *> *nodes) {
  (*count)++;
  
  struct Node *node = nodes->at(n);

  if (!node->visited) {
    node->firstVisitedTime = *count;
    node->visited = true;
  }  

  //  std::cout << (*count) << " = " << n << std::endl;

  std::list<int> *neighbors = graph->at(n);

  while (!neighbors->empty()) {
    int v = neighbors->front();
    neighbors->pop_front();
    
    if (!nodes->at(v)->visited) {
      visit(count, v, graph, nodes);
    }
  }

  (*count)++;
  node->lastVisitedTime = (*count);

  //  std::cout << (*count) << " = " << n << std::endl;
}

int main(void) {
  std::cin.tie(0);
  std::ios::sync_with_stdio(false);  

  int n = 0;
  std::cin >> n;

  std::vector<std::list<int> *> *graph = new std::vector<std::list<int> *>(n + 1);
  std::vector<struct Node *> *nodes = new std::vector<struct Node *>(n + 1);
  
  for (int i = 1; i <= n; i++) {
    int v = 0;
    std::cin >> v;

    int k = 0;
    std::cin >> k;

    std::list<int> *neighbors = new std::list<int>();

    for (int i = 0; i < k; i++) {
      int a = 0;
      std::cin >> a;

      neighbors->push_back(a);
    }

    graph->at(i) = neighbors;

    struct Node *node = (struct Node *) std::malloc(sizeof(struct Node));

    node->v = i;
    node->firstVisitedTime = 0;
    node->lastVisitedTime = 0;
    node->visited = false;
    
    nodes->at(i) = node;
  }

  int count = 0;
  int start = 1;

  visit(&count, start, graph, nodes);  

  for (std::vector<struct Node *>::iterator iterator = nodes->begin() + 1; iterator != nodes->end(); ++iterator) {
    struct Node *node = *iterator;
        
    std::cout << node->v << " " << node->firstVisitedTime << " " << node->lastVisitedTime << std::endl;
  }
  
  return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
#define FOR(i, a, b) for (int i = a; i < b; ++i)
#define ALL(vec) vec.begin(), vec.end()
#define rALL(vec) vec.rbegin(), vec.rend()
using namespace std;
using ll = long long;

vector<int> d, f, color;
vector<vector<int>> A;
int cnt = 0;

int next(int i) {
    for (auto j : A[i]) {
        if (color[j] == 0) {
            d[j] = cnt;
            color[j] = 1;
            return j;
        }
    }
    f[i] = cnt;
    color[i] = 2;
    return -1;
}

void dfs(int u) {
    cnt += 1;
    stack<int> S;
    S.push(u);
    d[u] = cnt;
    color[u] = 1;
    while (!S.empty()) {
        cnt += 1;
        int i = S.top();
        int j = next(i);
        if (j != -1) S.push(j);
        else S.pop();
    }
}

int main() {
    int n;
    cin >> n;
    A = vector<vector<int>>(n, vector<int>(0));
    d = vector<int>(n, 0);
    f = vector<int>(n, 0);
    color = vector<int>(n, 0);
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        rep(j, k) {
            int tmp;
            cin >> tmp;
            A[i].push_back(--tmp);
        }
    }
    rep(i, n) {
        if (color[i] == 0) dfs(i);
    }
    rep(i, n) {
        printf("%d %d %d\n", i + 1, d[i], f[i]);
    }
    return 0;
}