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 INFTY = (1 << 21)
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]: 頂点1から頂点iまでの距離
var color, d [MAX]int

func bfs(s int) {
	var q []int
	q = append(q, s)
	for i := 0; i < n; i++ {
		d[i] = INFTY
	}
	//sは開始点なので、0をいれる
	d[s] = 0

	//キューが空になるまで、以下を繰り返す
	for len(q) > 0 {
		u := q[0]
		q = q[1:]
		for v := 0; v < n; v++ {
			if M[u][v] == 0 {
				continue
			}
			if d[v] != INFTY {
				continue
			}
			d[v] = d[u] + 1
			q = append(q, v)
		}
	}

	for i := 0; i < n; i++ {
		fmt.Printf("%d ", i+1)
		if d[i] == INFTY {
			fmt.Printf("%d\n", -1)
		} else {
			fmt.Printf("%d\n", d[i])
		}
	}
}

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

			}
		}

	}

	bfs(0)

}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <cmath>
#include <cstring>

#define LP(i,n) for(int i=0;i<n;i++)
#define Mset(x,v) memset(x,v,sizeof(x))

using namespace std;
using LL=long long;
const int INF=100000000;

int A[110][110],d[100];

int main(){
    int n,u,k,v;
    cin>>n;
    LP(i,n){
        cin>>u>>k;
        LP(j,k){
            cin>>v;
            A[u-1][v-1]=1;
        }
    }
    queue<int> q;
    q.push(0);
    LP(i,n) d[i]=INF;
    d[0]=0;
    int x=0;
    while(!q.empty()){
        x=q.front();
        q.pop();
        LP(i,n){
            if(A[x][i]==0) continue;
            if(d[i]!=INF) continue;
            d[i]=d[x]+1;
            q.push(i);
        }
    }
    LP(i,n){
        cout<<i+1<<" "<<((d[i]==INF)?(-1):d[i])<<endl;
    }
    return 0;
}

C++: #include<iostream>
#include<queue>
#include<algorithm>
#define INF 999999999
using namespace std;

int res[101];
int G[101][101] = {0};

int main() {
    int n, u, v, k;
    std::queue<int> Q;
    std::cin >> n;
    for (int i = 0; i < n; i++) {
        std::cin >> u >> k;
        for (int j = 0; j < k; j++) {
            std::cin >> v;
            G[u - 1][v - 1] = 1;
        }
    }

    for (int i = 0; i < n; i++) res[i] = INF;

    Q.push(0);
    res[0] = 0;

    while (! Q.empty()) {
        u = Q.front();
        for (int i = 0; i < n; i++) {
            if (G[u][i]) {
                Q.push(i);
                res[i] = std::min(res[i], res[u] + 1);
            }
        }
        Q.pop();
    }

    for (int i = 0; i < n; i++) {
        if (res[i] != INF) std::cout << i + 1 << " " << res[i] << "\n";
        else std::cout << i + 1 << " -1\n";
    }

    return 0;
}

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

// macro
#define rep(i,n) for(i=0;i<n;i++)
#define ll long long
#define all(v) v.begin(), v.end()

// code starts
#define INF 1000000

int main()
{
  int n;cin>>n;
  int i,j;
  vector<vector<int>> g(n);
  rep(i,n)
  {
    int u,k;cin>>u>>k;
    u--;
    rep(j,k)
    {
      int vj;cin>>vj;
      vj--;
      g[u].emplace_back(vj);
    }
  }
  queue<int> q;
  queue<int> q2;
  q.push(0);
  vector<int> ans(n,INF);
  ans[0]=0;
  while(!q.empty())
  {
    while(!q.empty())
    {
      int now=q.front();
      q.pop();
      rep(i,g[now].size())
      {
        if(ans[g[now][i]]==INF)
        {
          q2.push(g[now][i]);
          ans[g[now][i]]=ans[now]+1;
        }
      }
    }
    while(!q2.empty())
    {
      q.push(q2.front());
      q2.pop();
    }
  }
  rep(i,n)
  {
    cout<<i+1<<' ';
    if(ans[i]==INF)cout<<-1<<endl;
    else cout<<ans[i]<<endl;
  }
}

C++: //単一始点最短経路
#include<iostream>
using namespace std;
static const int MAX=100;
static const int INFTY=(1<<21);
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;

int n,M[MAX][MAX];

void dijkstra(){
    int minv;
    int d[MAX],color[MAX];

    for(int i=0; i<n; i++){
        d[i]=INFTY;
        color[i]=WHITE;
    }

    d[0]=0;
    color[0]=GRAY;

    while(1){
        minv=INFTY;
        int u=-1;
        for(int i=0; i<n; i++){
            if(minv>d[i] && color[i]!=BLACK){
                u=i;
                minv=d[i];
            }
        }
        if(u==-1){ break; }
        color[u]=BLACK;
        for(int v=0; v<n; v++){
            if(color[v]!=BLACK &&  M[u][v]!=INFTY){
                if(d[v]>d[u]+M[u][v]){
                    d[v]=d[u]+M[u][v];
                    color[v]=GRAY;
                }
            }
        }
    }
    for(int i=0; i<n; i++){
        cout<<i<<" "<<(d[i]==INFTY ? -1 : d[i])<<endl;
    }
}

int main(){
    cin>>n;
    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            M[i][j]=INFTY;
        }         
    }

    int k,c,u,v;
    for(int i=0; i<n; i++){
        cin>>u>>k;
        for(int j=0; j<k; j++){
            cin>>v>>c;
            M[u][v]=c;
        }
    }

    dijkstra();
    return 0;
}

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

using namespace std;

void bfs(int v,vector<vector<int>>& vertex, int d[]);

//int depth = 0;

int main(){
    int n;
    cin >> n;
    int num;
    int tmp2;
    int d[n];
    for(int i=0;i<n;i++){
        d[i] = -1;
    }
    vector<vector<int>> vertex;
    vector<int> tmp;
    for(int i=0;i<n;i++){
        cin >> num;
        cin >> num;
        for(int j=0;j<num;j++){
            cin >> tmp2;
            tmp.push_back(tmp2-1);
        }
        vertex.push_back(tmp);
        tmp.clear();
    }
    bfs(0, vertex, d);
    
    for(int i=0;i<n;i++){
        cout << i+1 << " " <<  d[i] << endl;
    }
    return 0;
}

void bfs(int v, vector<vector<int>>& vertex, int d[]){
    queue<int> Q;
    Q.push(v);
    d[v] = 0;
    while(!Q.empty()){
        v = Q.front();
        Q.pop();
        bool flag = false;
        for(int i : vertex[v]){
            if(d[i]==-1){
                d[i] = d[v] + 1;
                Q.push(i);
                flag = true;
            }
        }
    }
}

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

typedef long long ll;
typedef pair<ll, ll> P;

#define pb push_back
#define rep(i, n) for(int i = 0; i < (n); i++)
#define FOR(i, a, n) for(int i = a; i < (n); i++)
#define mod (ll)(1e9+7)
#define int ll

static const int N = 100;
static const int no = -1;

__attribute__((constructor))
void initial() {
  cin.tie(0);
  ios::sync_with_stdio(false);
}

ll graph[N][N] = {{}}, d[N] = {}, n;

void bfs(int v) {
  queue<int> q;
  q.push(v);
  ll u;
  for(int i = 1; i <= n; i++) d[i] = no;
  d[v] = 0;
  while(!q.empty()) {
    u = q.front(); q.pop();
    for(int i = 1; i <= n; i++) {
      if(graph[u][i] == 0 continue;
      if(d[i] != no) continue;
      d[i] = d[u] + 1;
      q.push(i);
    }
  }
}

signed main() {
	ll u, v, k;
  cin >> n;
  rep(i, n) {
    cin >> u >> k;
    rep(j, k) {
      cin >> v;
      graph[u][v] = 1;
    }
  }

  bfs(1);

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

	return 0;
}