Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	timer := 1
	startNode := 1
	for {
		visit(startNode, &timer, childrenMap, timeRecordMap)
		startNode = findStartNode(childrenMap, timeRecordMap)
		if startNode < 0 {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	return x
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: //?????????????????¢?´¢
//??????????????????????????????????????¢?´¢
#include<iostream>
#include<cstdio>
#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?????£??\??????v?????????????????¨???
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(){
    int u;
    for(int i = 0; i < n; i++) nt[i] = 0;
    
    for( u = 0; u < n; u++){
        //????¨????u?????¢??????????????????dfs
        if(d[u] == WHITE) dfs_visit(u);
    }
    
    for( int i = 0; i < n; i++){
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
}

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

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

using namespace std;

#define MAX 110
int num;
int matrix[MAX][MAX];
int dst[MAX];

void input(){
    cin >> num;
    for(int i=0;i<MAX;i++){
        dst[i] = -1;
        for(int j=0;j<MAX;j++){
            matrix[i][j] = 0;
        }
    }
    for(int i=1;i<=num;i++){
        int v; cin >> v;
        int tmp; cin >>tmp;
        for(int j=0;j<tmp;j++){
            int vi; cin >> vi;
            matrix[v-1][vi-1] = 1;
        }
    }
}

void dfs(){
    stack<int> S;
    S.push(0);
    dst[0] = 0;
    while(S.size() != 0){
        int cur = S.top();
        S.pop();
        for(int i=0;i<num;i++){
            if(matrix[cur][i]==1){
                if(dst[i]==-1 ){
                    S.push(i);
                    dst[i] = dst[cur] + 1;
                }
            }
        }
    }
    for(int i=0;i<num;i++){
        cout << i+1 << " " <<  dst[i] << endl;
    }
}

int main(){
    input();
    dfs();
}

C++: #include<iostream>
#include<cstdio>
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+1][N+1];
int color[N+1],d[N+1],f[N],tt;
void dfs_visit(int u){
    int v;
    color[u]=GRAY;
    d[u]=++tt;
    for(int v=1;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=1;u<=n;u++)color[u]=WHITE;
    tt=0;
    for(int u=1;u<=n;u++){
        if(color[u]==WHITE)dfs_visit(u);
    }
    for(int u=1;u<=n;u++)
        cout<<u<<" "<<d[u]<<" "<<f[u]<<"\n";
}
int main(){
    int u,v,k;
    cin>>n;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++)
            M[i][j]=0;
    }
    for(int i=1;i<=n;i++){
        cin>>u>>k;
        for(int j=1;j<=k;j++){
            cin>>v;
            M[u][v]=1;
            
        }
    }
    dfs();
    return 0;
}

C++: //By Vlgd
#include<bits/stdc++.h>
using namespace std;
int g[101][101]={0},n,vis[101]={0};
int t=0,d[101],f[101];
/*
void dfs(int u){
	d[u]=++t;
	vis[u]=1;
	for(int v=1;v<=n;v++) if (!vis[v]&&g[u][v]==1) dfs(v);
	f[u]=++t;
}*/
stack<int>S;
void dfs2(int i){
	S.push(i); 
	vis[i]=1;
	d[i]=++t;
	while(!S.empty()){
		int u=S.top(),w=-1;
		for (int i=1;i<=n;i++) if (!vis[i]&&g[u][i]==1){w=i;break;}
		if (w!=-1){
			vis[w]=1;
			d[w]=++t;
			S.push(w);
		}
		else{
			f[u]=++t;
			S.pop();
		}
	}
} 
main(){
	int u,v,deg;
	scanf("%d",&n);
	for (int i=0;i<n;i++){
		scanf("%d%d",&u,&deg);
		for (int j=0;j<deg;j++){
			scanf("%d",&v);
			g[u][v]=1;
		}
	}
	for (int i=1;i<=n;i++) if (!vis[i]) dfs2(i);
	for (int i=1;i<=n;i++) printf("%d %d %d\n",i,d[i],f[i]);
}
/*
4
1 1 2
2 1 4
3 0
4 1 3

6
1 2 2 4
2 1 5
3 2 5 6
4 0
5 1 4
6 1 6
*/

C++: #include<iostream>
#include<vector>
using namespace std;
vector<vector<int>> G(100);
vector<pair<int,int>> D(100);
bool visited[100];
int elapse = 1;
void dfs(int x){
    if(visited[x]) return;
    visited[x] = true;
    D[x].first = elapse;
    elapse++;
    for(auto &a:G[x]) dfs(a);
    D[x].second = elapse;
    elapse++;
}
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin>>N;
    for(int i=0;i<N;++i){
        int u,k;
        cin>>u>>k;
        for(int j=0;j<k;++j){
            int v;
            cin>>v;
            G[u-1].push_back(--v);
        }
    }
    dfs(0);
    for(int i=0;i<N;++i) cout<<i+1<<' '<<D[i].first<<' '<<D[i].second<<endl;
}