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 <iostream>
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 u = 0; u < n; u++) {
        cout << u + 1 << " " << d[u] << " " << f[u] << endl;
    }
}

int main() {
    int u, v, k;

    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();
}

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

int next(int u){
	for(int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
		if(M[u][v] == 1) 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 {
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


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

C++: //ALDS1_11B
#include <iostream>
#include <vector>
#include <cstdio>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;

int n;
int color[N],d[N],f[N],tt;
vector< vector<int> > M(N,vector<int>(N));

void dfs_visit(int u){
 int v;
 color[u]=GRAY;
 d[u]=++tt;
 for(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(){
 int u;
 for(u=0;u<n;u++) color[u]=WHITE;
 tt=0;
 for(u=0;u<n;u++){
  if(color[u]==WHITE) dfs_visit(u);
 }
 for(u=0;u<n;u++){
  printf("%d %d %d\n",u+1,d[u],f[u]);
 }
}

int main(){
 int u,v,k,i,j;
 scanf("%d",&n);
 for(i=0;i<n;i++){
  scanf("%d %d",&u,&k);
  u--;
  for(j=0;j<k;j++){
   scanf("%d",&v);
   v--;
   M[u][v]=1;
  }
 }
 dfs();
 return 0;
}

C++: #include <bits/stdc++.h>
#define FOR(i, a, b) for(int i = (a); i < (b); ++i)
#define REP(i, n) for(int i = 0; i < (n); ++i)
#define SORT(v) sort(v.begin(), v.end());
#define pb(a) push_back(a)
using ll = long long;
using namespace std;

#define WHITE 1
#define GRAY 2
#define BLACK 3

int now, n, u, k, v, tree[102][102], timeTable[102][2], color[102], timeNow = 1;
stack<int> st;

void dfs(){
    while(1){
        if(st.empty()){
            FOR(l, 1, n + 1){
                cout << l << " " << timeTable[l][0] << " " << timeTable[l][1] << endl;
            }
            break;
        }else{
            now = st.top();
          	if(color[now] == WHITE){
            	timeTable[now][0] = timeNow;
            }
            color[now] = GRAY;
            int cnt = 1;
            while(1){
                if(cnt == n + 1){
                    st.pop();
                    color[now] = BLACK;
                    timeTable[now][1] = timeNow + 1;
                    break;
                }else if(tree[now][cnt] && color[cnt] == WHITE){
                    st.push(cnt);
                    break;
                }
                cnt++;
            }
            timeNow++;
        }
    }
}

int main(){
    cin >> n;
  	REP(i, 102){
    	REP(j, 102){
        	tree[i][j] = 0;
        }
    }
    REP(i, n){
        cin >> u >> k;
        color[i + 1] = WHITE;
        REP(j, k){
            cin >> v;
            tree[u][v] = 1;
        }
    }
    st.push(1);
    dfs();
  	return 0;
}

C++: #include<iostream>
#include<cmath>
#include<algorithm>
#include<string>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<iomanip>
#include<bitset>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;
typedef pair<ll,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define fi first
#define sc second
#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())

const int MAX = 510000;
const int MOD = 1000000007;
using Graph = vector<vector<ll> >;

vector<bool> seen;
vector<ll> first_order;
vector<ll> last_order;

void dfs(const Graph &G, ll v, ll& ptr) {
    // 行きがけ順をインクリメントしながらメモ
    first_order[v] = ptr++;

    seen[v] = true;
    for (auto next_v : G[v]) {
        if (seen[next_v]) continue;
        dfs(G, next_v, ptr);
    }

    // 帰りがけ順をインクリメントしながらメモ
    last_order[v] = ptr++;
}

int main(){
  ll N; cin >> N;
  Graph G(N);

  rep(i,N){
    ll a; cin >> a;
    ll k; cin >> k;
    rep(j,k){
      ll to; cin >> to; to--;
      G[i].pb(to);
    }
  }

  seen.assign(N, false);
  first_order.resize(N);
  last_order.resize(N);

  ll ptr = 1;

  rep(i, N){
    if(!seen[i]) dfs(G, i, ptr);
  }

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