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 <vector>
#include <algorithm>

using namespace std;

const int WHITE = 0, GREY = 1, BLACK = 2;

struct DFS {
    int n;
    vector<vector<int>> g;
    vector<int> color;
    vector<int> dt;
    vector<int> ft;
    int ct = 1;
 
    DFS(int n) : n(n) {
        g.assign(n, vector<int>());
        color.assign(n, WHITE);
        dt.assign(n, -1);
        ft.assign(n, -1);
    }
    
    void solve() {
        for (int i = 0; i < n; i++) {
            if (color[i] == WHITE) {
                dfs(i);
            }
        }
    }
    
    void dfs(int u) {
        //cout << "visit " << u << endl;
        color[u] = GREY;
        dt[u] = ct++; 
        for (int v : g[u]) {
            if (color[v] == WHITE) {
                dfs(v);
            }
        }
        ft[u] = ct++;
        color[u] = BLACK;
    }
    
    void addEdge(int u, int v) {
        g[u].push_back(v);
    }
    
    void printGraph() {
        for (int i = 0; i < n; i++) {
            cout << i << ": ";
            for (int v : g[i]) {
                cout << v << " ";
            }
            cout << endl;
        }
    }
        
};


int main() {   
    int n;
    cin >> n;
    DFS dfs(n);
   
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            v--;
            dfs.addEdge(u, v);
        }  
    }
    
    //dfs.printGraph();
    
    dfs.solve();
    
    for (int i = 0; i < n; i++) {
        cout << (i + 1) << " " << dfs.dt[i] << " " << dfs.ft[i] << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <cstring>
#define N 101

using namespace std;

int visited[N], discovery[N], finish[N], tt, n;
vector<int> G[N];

void dfs(int u) {
    visited[u] = 1;
    discovery[u] = ++tt;
    for (int i = 0; i < G[u].size(); i++) {
        if (visited[G[u][i]] == 0) {
            dfs(G[u][i]);
        }
    }
    finish[u] = ++tt;
}

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

    cin >> n;

    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            cin >> v;
            v--;
            G[u].push_back(v);
        }
    }
    memset(visited, 0, sizeof(visited));
    tt = 0;

    for (int i = 0; i < n; i++) {
        if (visited[i] == 0) {
            dfs(i);
        }
    }

    for (int i = 0; i < n; i++) {
        cout << i + 1 << " " << discovery[i] << " " << finish[i] << endl;
    }

    return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
using namespace std;
int inf = 1000000000;

class Graph{
public:
  int v;
  int ftime = -1;
  int ltime = -1;
  vector<int> e;
};
vector<Graph> g;
int cnt = 0;
void dfs(int pos){
  if( g[pos].ftime != -1 ) return;
  cnt++;
  g[pos].ftime = cnt;
  for(int i=0; i<g[pos].e.size(); i++){
    dfs(g[pos].e[i]);
  }
  cnt++;
  g[pos].ltime = cnt;
}

int main(void) {

  int n;
  cin >> n;
  g.resize(n);
  int u, k;
  for(int i=0; i<n; i++){
    cin >> u >> k;
    u--;
    g[u].v = u;
    g[u].e.resize(k);
    for(int j=0; j<k; j++){
      cin >> g[u].e[j];
      g[u].e[j]--;
    }
    sort(g[u].e.begin(), g[u].e.end());
  }
  for(int i=0; i<n; i++) dfs(i);
  for(int i=0; i<n; i++){
    cout << g[i].v + 1 << " " << g[i].ftime << " " << g[i].ltime << endl;
  }



  return 0;
}

// EOF

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

using namespace std;

int tim = 0;
vector<vector<int>> to;
vector<bool> reached;
vector<int> d;
vector<int> f;



void dfs(int point);

int main()
{
    int n;
    cin >> n;
    to.resize(n+1);
    for(int i = 1; i <= n; i++){
        int m;
        cin >> m;
        cin >> m;
        to[i].resize(m);
        for(int j = 0; j < m; j++){
            cin >> to[i][j];
        }
    }
    
    reached.resize(n+1);
    d.resize(n+1);
    f.resize(n+1);

    for(int i = 1; i <=n; i++){
        if(!reached[i]){
            dfs(i);
        }
    }

    for(int i = 1; i <= n; i++){
        cout << i << " " << d[i] << " " << f[i] << endl;
    }

    return 0;
}

void dfs(int point)
{
    tim++;
    reached[point] = true;
    d[point] = tim;

    for(int i = 0; i < to[point].size(); i++){
        if(!reached[to[point][i]]){
            dfs(to[point][i]);
        }
    }
    tim++;
    f[point] = tim;    

}

C++: #include <cstdio>
#include <vector>
#include <algorithm>
#include <stack>

using namespace std;

using Weight=int;
using DArray=vector<Weight>;
using DMatrix=vector<DArray>;

static const Weight INF=1<<29;

struct Edge {
    size_t src, dst;
    Weight weight;
    Edge() {}
    Edge(size_t src, size_t dst, Weight weight=1):
        src(src), dst(dst), weight(weight)
    {}
};

bool operator<(const Edge &e, const Edge &f) {
    if (e.weight != f.weight) {
        return e.weight > f.weight;
    } else {
        return e.src!=f.src? e.src<f.src : e.dst<f.dst;
    }
}

using Edges=vector<Edge>;
using Vertex=vector<Edge>;
using Graph=vector<Vertex>;

void join(Graph &g, size_t s, size_t d, Weight w=1) {
    // non-directed
    g[s].push_back(Edge(s, d, w));
    g[d].push_back(Edge(d, s, w));
}

void connect(Graph &g, size_t s, size_t d, Weight w=1) {
    // directed
    g[s].push_back(Edge(s, d, w));
}

void dfs(const Graph &g, size_t v, int &t, vector<int> &d, vector<int> &f) {
    d[v] = t;
    for (const Edge &e: g[v])
        if (!d[e.dst])
            dfs(g, e.dst, ++t, d, f);

    f[v] = ++t;
}

int main() {
    size_t n;
    scanf("%zu", &n);

    Graph g(n);
    for (size_t i=0; i<n; ++i) {
        size_t k;
        scanf("%*d %zu", &k);
        for (size_t j=0; j<k; ++j) {
            size_t v;
            scanf("%zu", &v);
            --v;

            connect(g, i, v);
        }
    }

    vector<int> d(n), f(n);
    int t=1;
    for (size_t v=0; v<n; ++v)
        if (!d[v])
            dfs(g, v, t, d, f);

    for (size_t i=0; i<n; ++i)
        printf("%zu %d %d\n", i+1, d[i], f[i]);

    return 0;
}