Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

C++: #include<iostream>
#include<stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;

int n, M[N][N];
int color[N], d[N], f[N], tt;
int nt[N];

//uに隣接するvを番号順に取得
int next(int u) {
    for(int v = nt[u]; v < n; v++) {
        nt[u] = v + 1;
        if(M[u][v]) return v;
    }
    return -1;
}

void dfs_visit(int r) {
    for(int i = 0; i < n; i++) nt[i] = 0;
    
    stack<int> S;
    S.push(r);
    color[r] = GRAY;
    d[r] = ++tt;
    
    while(!S.empty()) {
        int u = S.top();
        int v = next(u);
        if(v != -1) {
            if(color[v] == WHITE) {
                color[v] = GRAY;
                d[v] = ++tt;
                S.push(v);
            }
        }else {
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

void dfs() {
    //初期化
    for(int i = 0; i < n; i++) {
        color[i] = WHITE;
        nt[i] = 0;
    }
    tt = 0;
    
    for(int u = 0; u < n; u++) {
        if(color[u] == WHITE) dfs_visit(u);
    }
    for(int i = 0; i < n; i++) {
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
}

int main() {
    int u, k, v;
    
    cin >> n;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < n; j++) {
            M[i][j] = 0;
        }
    }
    
    for(int i = 0; i < n; i++) {
        cin >> u >> k;
        u--;
        for(int j = 0; j < k; j++) {
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }
    
    dfs();
    
    return 0;
}

C++: // clang-format off
#include <bits/stdc++.h>
#define int long long
#define main signed main()
// #define main int main()
#define loop(i, a, n) for (int i = (a); i < (n); i++)
#define rep(i, n) loop(i, 0, n)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define prec(n) fixed << setprecision(n)
#define stlice(from, to) substr(from, (to) - (from) + 1)
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define fi first
#define se second
using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<pii> vpii;
typedef vector<vi> vvi;
typedef vector<vb> vvb;
typedef vector<vpii> vvpii;
const int INF = sizeof(int) == sizeof(long long) ? 1000000000000000000LL : 1000000000;
const int MOD = 1000000007;
const double PI = acos(-1);
template<typename A, typename B> bool cmin(A &a, const B &b) { return a > b ? (a = b, true) : false; }
template<typename A, typename B> bool cmax(A &a, const B &b) { return a < b ? (a = b, true) : false; }
bool odd(const int &n) { return n & 1; }
bool even(const int &n) { return !odd(n); }
void solve();
main { solve(); return 0; }
// clang-format on

typedef int Weight;

struct Edge {
  int src, dst;
  Weight weight;
  Edge(int s, int d, Weight w)
    : src(s), dst(d), weight(w) {
  }
};

typedef vector<Edge> Edges;
typedef vector<Edges> Graph;
typedef vector<Weight> Array;
typedef vector<Array> Matrix;

void addEdge(Graph &g, int a, int b, Weight w = 1) {
  g[a].emplace_back(a, b, w);
  g[b].emplace_back(b, a, w);
}

void addArc(Graph &g, int a, int b, Weight w = 1) {
  g[a].emplace_back(a, b, w);
}

void solve() {
  int n;
  cin >> n;
  Graph g(n);
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    u--;
    while (k--) {
      int v;
      cin >> v;
      v--;
      addArc(g, u, v);
    }
  }
  int c = 1;
  vi done(n);
  vpii time(n);
  function<void(int)> dfs = [&](int x) {
    if (done[x]) return;
    done[x]    = true;
    time[x].fi = c++;
    for (Edge e : g[x]) {
      dfs(e.dst);
    }
    time[x].se = c++;
  };
  rep(i, n) dfs(i);
  rep(i, n) {
    cout << i + 1 << ' ' << time[i].fi << ' ' << time[i].se << endl;
  }
}

C++: 
#include<iostream>
#include<stack>
using namespace std;
#define NIL -999
bool mark[105][105];
int n;
int tm = 0;
int d[105] = { 0 };
int f[105] = { 0 };

inline int next(int i) {
	for (int tmp = 1; tmp <= n; ++tmp) {
		if (mark[i][tmp] && !d[tmp]) {
			//cout << endl << i << "的下一个节点是：" << tmp << endl;
			return tmp;
		}
	}
	//cout << endl << i << "的下一个节点是：" << NIL << endl;
	return NIL;
}

void dfs_IN(int i) {
	stack<int> s;
	int now = i, nt;
	d[i] = ++tm;
	s.push(i);
	//	s.push(i);
	//	d[i] = ++tm;
	//first solution
	/*do {
		//		cout<<"visit: "<<now<<endl;
		if (!s.empty()) {
			now = s.top();
			s.pop();
		}
		do {
			//cout << "visit: " << now << endl;
			nt = next(now);
			if (nt != NIL && !d[nt]) {
				s.push(now);
				d[nt] = ++tm;
				now = nt;
			}
			else break;
		} while (true);
		//cout << "end visit:  " << now << endl;
		f[now] = ++tm;
		
	} while (!s.empty());*/
	//solution 2
	while (!s.empty()) {
		now = s.top();
		nt = next(now);
		if (nt != NIL) {
			d[nt] = ++tm;
			s.push(nt);
		}
		else {
			s.pop();
			f[now] = ++tm;
		}
	}
}

void dfs() {
	for (int i = 0; i <= n + 2; ++i)
		for (int k = 1; k <= n + 2; ++k)
			mark[i][k] = false;

	int Node, k, tmp;
	cin >> n;
	for (int l = 0; l<n; l++) {
		cin >> Node >> k;
		for (int x = 0; x<k; x++) {
			cin >> tmp;
			mark[Node][tmp] = true;
		}
	}

	for (int p = 1; p <= n; ++p)
		if(!d[p])dfs_IN(p);

	for (int p = 1; p <= n; ++p)
		cout << p << ' ' << d[p] << ' ' << f[p] << endl;

}

int main() {

	dfs();
	return 0;
}

C++: #include<iostream>
using namespace std;

#define NIL 0

struct Node{
    int d=0, f=0, ch=0;
    int child[100]={0};
};

Node nodes[101];

int search(int num, int time){
    if(nodes[num].d!=NIL){
        return time;
    }
    nodes[num].d = time;
    ++time;
    for(int i=0;i<nodes[num].ch;++i){
        time = search(nodes[num].child[i], time);
    }
    nodes[num].f = time;
    ++time;
    return time;
}

int main(){
    
    int n, num=0, time = 1;
    cin >> n;
    for(int i=1;i<=n;++i){
        cin>>num;
        cin >> nodes[num].ch;
        for(int j=0;j<nodes[num].ch;++j){
            cin >> nodes[num].child[j];
        }
    }
    
    
    for(int i=1;i<=n;++i){
        if(nodes[i].d==NIL){
            time = search(i, time);
        }
    }
    
    
    for(int i=1;i<=n;i++){
        cout << i << " " << nodes[i].d << " " <<nodes[i].f << endl;
        
    }
    
    
    
    return 0;
}