Go: package main

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

const MAX = 101

var f [MAX]int
var d [MAX]int
var list [][]int
var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

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

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(u, cnt int) int {
	if d[u] != 0 {
		return cnt
	}

	cnt++
	d[u] = cnt
	for _, next := range list[u] {
		cnt = dfs(next, cnt)
	}
	cnt++
	f[u] = cnt
	return cnt
}

func main() {
	n := scanInt()
	list = make([][]int, n+1)
	for i := 1; i <= n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			n := scanInt()
			list[u] = append(list[u], n)
		}
	}

	cnt := 0
	for i := 1; i <= n; i++ {
		cnt = dfs(i, cnt)
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, d[i])
		fmt.Fprint(w, " ")
		fmt.Fprint(w, f[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

C++: #include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

#define pb push_back
#define debug(x) cout<< #x <<": "<<x<<endl
#define debug2(x,y) cout<< #x <<": "<< x <<", "<< #y <<": "<< y <<endl

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<i_i, int> p_i;
typedef vector<int> vi;
typedef vector<vector<int> > vvi;
template<class T> using vv=vector<vector< T > >;

vi ts_d;
vi ts_f;

template<class T>
void dfs(int cur, int &time_visit, T graph) {
  // visiting cur
  time_visit += 1;
  ts_d[cur] = time_visit;
  for (auto dst : graph[cur]) {
    if (ts_d[dst] == 0) {
      dfs(dst, time_visit, graph);
    }
  }
  time_visit += 1;
  ts_f[cur] = time_visit;
}

int main() {
  int time = 0;
  int n;
  cin >> n;
  ts_d.reserve(n);
  ts_f.reserve(n);
  ts_d.assign(1, 0);
  vector<set<int> > graph(n, set<int>());

  for (int i = 0; i < n; ++i) {
    int num;
    cin >> num;
    num -= 1;
    int out;
    cin >> out;
    for (int j = 0; j < out; ++j) {
      int tmp;
      cin >> tmp;
      tmp -= 1;
      graph[i].insert(tmp);
    }
  }

  dfs(0, time, graph);

  for (int i = 0; i < n; ++i) {
    printf("%d %d %d\n", i+1, ts_d[i], ts_f[i]);
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, a) for(int i=0; i<(int)(a); i++)
vector<vector<int>> a;
vector<int> b;
vector<int> s;
vector<int> t;
int c = 1;

void dfs(int x)
{
  if (b[x]==1) return;
  b[x] = 1;
  s[x] = c; c++;
  for (auto v:a[x]) {
    dfs(v);
  }
  t[x] = c; c++;
}

int main()
{
  int n; cin>>n;
  a.resize(n);
  b.resize(n); rep(i, n) b[i]=0;
  s.resize(n); rep(i, n) s[i]=0;
  t.resize(n); rep(i, n) t[i]=0;
  rep(i, n) {
    int u; cin>>u; u--;
    int k; cin>>k;
    rep(j, k) {
      int v; cin>>v; v--;
      a[u].push_back(v);
    }
  }
  rep(i, n) dfs(i);
  rep(i, n) printf("%d %d %d\n", i+1, s[i], t[i]);

  return 0;
}

C++: //#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define all(v) v.begin(), v.end()
using in = int64_t;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define REP(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
const double PI=3.14159265358979323846;
const in MOD = 1000000007;
const in INF=1<<30;
using P=pair<int,int>;
vector<int> dx={0,1,-1,0};
vector<int> dy={1,0,0,-1};

vector<vector<int>> a(0);
int g;
vector<int> s(0),t(0);
int cnt=1;

int dfs(int x){
    s[x]=cnt;
    cnt ++;
    for(auto y:a[x]){
        if(s[y]==-1){
            dfs(y);
        }
    }
    t[x]=cnt;
    cnt ++;
}

int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cout << fixed << setprecision(10);
    cin>>g;
    a=vector<vector<int>>(g,vector<int>(0));
    int k,x;
    rep(i,g){
        cin>>k;
        cin>>k;
        rep(j,k){
            cin>>x;
            a[i].emplace_back(x-1);
        }
    }
    s.resize(g,-1);t.resize(g,-1);
    rep(i,g){
        if(s[i]==-1) dfs(i);
    }
    rep(i,g) cout<<i+1<<" "<<s[i]<<" "<<t[i]<<'\n';
}

C++: #include <bits/stdc++.h>
#define ll long long
using namespace std;

struct ver{
    ll d;
    ll f;
};

ll t=0;
vector<vector<ll>> mat;
vector<ver> vers;

void find(ll pos) {
    t++;
    if(vers[pos].d == 0){
        vers[pos].d = t;
    }
    for(ll i:mat[pos]) {
        find(i);
    }
    t++;
    if(vers[pos].f == 0) {
        vers[pos].f = t;
    }
}

int main() {
    ll n;
    cin >> n;
    for(ll i=0;i<n;i++) {
        ll u,k;
        cin>>u>>k;
        vector<ll> aaa;
        for(ll j=0;j<k;j++) {
            ll tmp;
            cin>>tmp;
            aaa.push_back(tmp-1);
        }
        mat.push_back(aaa);
    }
    for(ll i=0;i<n;i++) {
        vers.push_back(ver{0,0});
    }
    find(0);
    for(ll i=0;i<n;i++) {
        cout << i+1<<" "<<vers[i].d<<" "<<vers[i].f<<endl;
    }
}

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;

void dfs_visit(int u) {
    color[u] = GRAY;
    d[u] = ++tt;
    for (int v=0; v < n; v++) {
        if (M[u][v] == 0) continue;
        if (color[v] == WHITE) {
            dfs_visit(v);
        }
    }
    color[u] = BLACK;
    f[u] = ++tt;
}

void dfs() {
    for (int u=0; u < n; u++) color[u] = WHITE;
    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() {
    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++) {
        int u, l; cin >> u >> l;
        u--;
        for (int j = 0; j < l; j++) {
            int v; cin >> v;
            v--;
            M[u][v] = 1;
        }
    }

    dfs();
    
    return 0;
}

C++: #include <vector>
#include <iostream>
using namespace std;
int n, u, k, v, t, d[100][2]; vector<int> g[100];
void rec(int pos) {
	d[pos][0] = ++t;
	for(int i = 0; i < g[pos].size(); i++) {
		if(!d[g[pos][i]][0]) rec(g[pos][i]);
	}
	d[pos][1] = ++t;
}
int main() {
	cin >> n;
	for(int i = 0; i < n; i++) {
		cin >> u >> k;
		for(int j = 0; j < k; j++) cin >> v, g[u - 1].push_back(v - 1);
	}
	for(int i = 0; i < n; i++) {
		if(!d[i][0]) rec(i);
	}
	for(int i = 0; i < n; i++) cout << i + 1 << ' ' << d[i][0] << ' ' << d[i][1] << endl;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cassert>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define rep(i,n) FOR(i,0,n)
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define vint vector<int>
#define vdouble vector<double>
#define vstring vector<string>
using namespace std;

#include<map>
#include<set>
#include<queue>

typedef long long ll;
typedef unsigned long long ull;

const int MAX_N = 1000000;

int N;
vint G[100];
int FLG[100];
int D[100];
int F[100];
const int NIL = -1;
int tt;

void dfs(int ii){

	tt++;
	D[ii] = tt;

	// cout << "reach " << ii << " " << tt << endl;

	rep(i, G[ii].size()){
		int to = G[ii][i];
		if (D[to] == NIL){
			dfs(to);
		}
	}

	tt++;
	F[ii] = tt;
	// cout << "back " << ii << " " << tt << endl;

}

void run_dfs(){
	rep(i, N){ D[i] = NIL; }
	int start = 0;
	tt = 0;
	rep(i, N){
		if (D[i] == NIL) dfs(i);
	}
}

int main() {

	cin >> N;
	rep(i, N){
		int id, n; cin >> id >> n; id--;
		rep(j, n){
			int id_to; cin >> id_to; id_to--;
			G[id].push_back(id_to);
		}
	}

	run_dfs();

	rep(i, N){
		cout << (i+1) << " " << D[i] << " " << F[i] << endl;
	}
}