Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

C++: #include <map>
#include <set>
#include <list>
#include <cmath>
#include <deque>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <utility>
#include <iostream>
#include <algorithm>
#include <functional>
#include <unordered_map>
#include <unordered_set>

using namespace std;

#define ll long long
#define ull unsigned long long
#define INF (1 << 30)
#define LLINF (1LL << 62)
#define MOD7 1000000007
#define MOD9 1000000009
#define eps 1e-9
#define P pair<int, int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pul pair<ull, ull>
#define all(a) (a).begin(), (a).end()
#define FOR(i,a,b) for (int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);--i)
#define REP(i,n) for (int i=0;i<(n);++i)
#define RREP(i,n) for (int i=(n)-1;i>=0;--i)

void YES() { cout << "YES\n"; }
void NO() { cout << "NO\n"; }
void Yes() { cout << "Yes\n"; }
void No() { cout << "No\n"; }
void yes() { cout << "yes" << endl; }
void no() { cout << "no" << endl; }

template<class T>
class DirectedGraph {
public:
	class Edge {
	public:
		int to;
		T cost;

		Edge(int t, T c) : to(t), cost(c) {}
	};

	vector<vector<Edge>> G;
	vector<int> visit;
	vector<pii> stamp{ 0 };
	int V;

	DirectedGraph(int n = 0) {
		resize(n);
	}

	void resize(int n) {
		V = n;
		G.resize(n);
		visit.resize(n);
		stamp.resize(n);
	}

	void addEdge(int from, int to, T cost = 0) {
		int v = max(from, to);
		if (v >= V)
			resize(v + 1);
		G[from].push_back(Edge(to, cost));
	}

	int t = 1;
	void dfs(int s) {
		if (stamp[s].first == 0)
			stamp[s].first = t++;
		else
			return;

		for (int i = 0; i < G[s].size(); ++i) {
			dfs(G[s][i].to);
		}
		stamp[s].second = t++;
	}

	int bfs() {

	}
};

int main() {
	DirectedGraph<int> g;
	int n, id, k, to;
	cin >> n;
	for (int i = 0; i < n; ++i) {
		cin >> id >> k;
		while (k--) {
			cin >> to;
			g.addEdge(id, to);
		}
	}

	for (int i = 1; i <= n; ++i) {
		g.dfs(i);
	}
	for (int i = 1; i <= n; ++i) {
		cout << i << " " << g.stamp[i].first << " " << g.stamp[i].second << endl;
	}

	return 0;
}

C++: #define TST 0
#include <iostream>
#include <fstream>
#include <string>
#include <cmath>
#include <vector>
#include <algorithm>
#include <functional>
#include <cstdio>
#include <cstdlib>
#include <iomanip>
#include <cctype>
#include <bits/stdc++.h>
#include <queue>

using namespace std;
// for loop
#define F(i, L, R) for(long i = L; i < R; i++)
#define FE(i, L, R) for(long i = L; i <= R; i++)
// for (reversed)
#define FR(i, L, R) for(long i = L; i > R; i--)
#define FRE(i, L, R) for(long i = L; i >= R; i--)

// data types
#define Int long
#define ul unsigned long
#define ll long long
#define ull unsigned long long
#define ui unsigned int
#define us unsigned shoft

// vectors
typedef vector<int> vi;
typedef vector<long> vl;
typedef vector<vi> vvi;
typedef pair<int, int> ii;
#define ALL(c) (c).begin(),(c).end()
#define last(vec) vec.size()-1
#define lastEle(vec) vec[last(vec)]
#define pb push_back
#define InputV(a, n) F(i,0,n){long l; cin >> l; a.pb(l);}

// debug
#define DBG(vari) cerr<<#vari<<" = "<<(vari)<<endl;
#define printA(a, L, R) FE(i, L, R) cout << a[i] << (i==R?'\n':' ')
#define printAF(a, L) printA(a, 0, L-1)
#define printV(a) printA(a, 0, a.size()-1)

// utils
#define char2int(c) (c-'0')
#define bit(x, i) (x&(1<<i))
#define space ' '
#define PI 3.14159265358979323

template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

void printM(vector<vector<int> > &vec, long height, long width){
    F(i, 0, height){
        F(j, 0, width){
            cout << vec[i][j] << space;
        }
    cout << endl;
    }
}

vector<int> seen;
vector<int> done;
int timestamp;

// Graph: グラフを表した隣接リスト
// v: 何番目のノードを訪問するのか
void dfs(vector<vector<int> > &Graph, int v){
    timestamp++;
    seen[v] = timestamp; //訪問済みにする

    // 隣接するノードを再帰的に訪問
    for(int next_v = 0; next_v < Graph[v].size();next_v++) {
        if(seen[Graph[v][next_v]] != -1) continue;
        dfs(Graph, Graph[v][next_v]);
    }
    // 出るときの時間が増える
    timestamp++;
    done[v] = timestamp; // 隣接ノードを全て調べ終えた
}

int main() {
#if TST==1
    ifstream in ("input.txt");
    cin.rdbuf(in.rdbuf());
#endif

    int u;
    int k;
    vector<vector<int> > Graph;
    cin >> u;
    int id;
    F(i, 0, u){
        cin >> id;
        cin >> k;
        vector<int> list = vector<int>(k);
        F(j, 0, k){
            cin >> list[j];
            list[j]--;
        }
        Graph.pb(list);
    }
    seen.assign(u, -1);
    done.assign(u, -1);
    timestamp = 0;

    F(i, 0, u){
        if(seen[i] == -1)dfs(Graph, i);
    }
    F(i, 0, u){
        cout << i+1 << space << seen[i] << space << done[i] << endl;
    }
#if TST==1
#endif
}