Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Queue struct {
	arr []int
}

func (q *Queue) push(v int) {
	q.arr = append(q.arr, v)
}

func (q *Queue) pop() int {
	res := q.arr[0]
	q.arr = q.arr[1:]
	return res
}

func (q *Queue) isEmpty() bool {
	return len(q.arr) == 0
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	var q Queue
	seen := make([]int, N)
	for i := 0; i < N; i++ {
		seen[i] = -1
	}
	var search func(cur int)
	search = func(cur int) {
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if seen[next] == -1 {
				q.push(next)
				seen[next] = seen[cur] + 1
			}
		}
	}
	q.push(0)
	seen[0] = 0
	for !q.isEmpty() {
		search(q.pop())
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i+1, seen[i])
	}
	wtr.Flush()
}

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


using namespace std;


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

int graph[N][N] = {{}};
int d[N] = {};
int n;

void bfs(int v){
  queue<int> Q; 
  Q.push(v);

  int 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);
    }
  }
}


int main(){
  int u,v,k;
  //graph
  cin >> n ;

  for(int i = 0; i < n; i++){
    cin >> u >> k ;
    for(int j = 0; j < k ; j++){
      cin >> v;
      graph[u][v] = 1;
    }
  }


  bfs(1);

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

  return 0;
}

C++: #include<iostream>
#include<queue>
#include<vector>
using namespace std;
int main(){
  queue<int> q;
  int n,a,k,u,c[101];
  vector<int>  d[101];
  cin>>n;for(int i=0;i<n;i++){
    cin>>u>>k;c[i+1]=-1;
    d[u].resize(k);
    for(int j=0;j<k;j++) cin>>d[u][j];
  }q.push(1),c[1]=0;
  while(!q.empty()){
   a=q.front(),q.pop();
    for(int i=0;i<d[a].size();i++)
      if( d[a][i]>1 && c[d[a][i]]==-1) q.push(d[a][i]),c[d[a][i]]=c[a]+1;
  } for(int i=1;i<=n;i++) cout<<i<<" "<<c[i]<<endl;
  return 0;
}

C++: #include <array>
#include <vector>
#include <deque>
#include <queue>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <string>
#include <algorithm>
#include <numeric>
#include <functional>
#include <iterator>
#include <tuple>
#include <utility>
#include <limits>
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cstdint>
#include <cassert>

using namespace std;

#define FOR(i, start, end) for(int i = (start); i < (end); ++i)
#define REP(i, n) FOR(i, 0, n)

int n;
int mat[100][100];
int d[100];

void solve()
{
    fill(begin(d), end(d), -1);

    queue<int> q;
    q.push(0);
    d[0] = 0;

    while(!q.empty()) {
        int i = q.front(); q.pop();
        REP(j, n) {
            if(!mat[i][j]) continue;
            if(d[j] != -1) continue;

            d[j] = d[i] + 1;
            q.push(j);
        }
    }
}

int main()
{
    cin >> n;

    REP(i, n) {
        REP(j, n) {
            mat[i][j] = 0;
        }
    }

    REP(_, n) {
        int u, k;
        cin >> u >> k;

        REP(_, k) {
            int v;
            cin >> v;
            mat[u-1][v-1] = 1;
        }
    }

    solve();

    REP(i, n) {
        cout << i+1 << " " << d[i] << "\n";
    }

    return 0;
}

C++: #include "bits/stdc++.h"

#define REP(i,num) for(ll i=0;i<(num);++i)
#define LOOP(i) while(i--)
#define ALL(c) c.begin(),c.end()
#define PRINTALL(c) for(auto pitr=c.begin();pitr!=c.end();++pitr){cout<<*pitr;if(next(pitr,1)!=c.end())cout<<' ';}cout<<endl;
#define PAIRCOMP(c,comp) [](const pair<ll,ll>& lhs,const pair<ll,ll>& rhs){return lhs.c comp rhs.c;}

using namespace std;
using ll = long long;

constexpr ll atcoder_mod = 1e9+7;

template<typename T=ll>
T in(){T x; cin >> x; return (x);}
template<typename T=ll,typename C=vector<T>>
C vecin(int N){C x(N);REP(i,N){x[i]=in<T>();}return move(x);}

void vout(){cout << endl;}
template<typename Head,typename... Tail>
void vout(Head&& h,Tail&&... t){cout << ' ' << h;vout(forward<Tail>(t)...);}
void out(){cout << endl;}
template<typename Head,typename... Tail>
void out(Head&& h,Tail&&... t){cout << h;vout(forward<Tail>(t)...);}

class ConnectNodeInfo{
	vector<vector<pair<ll,ll>>> graph;
public:
	ConnectNodeInfo(int node_num){
		graph.resize(node_num);
	}
	void AddNonDirectionalConnection(ll u,ll v,ll w){
		graph[u].emplace_back(v,w);
		graph[v].emplace_back(u,w);
	}
	void AddDirectionalConnection(ll u,ll v,ll w){
		graph[u].emplace_back(v,w);
	}
	vector<pair<ll,ll>>& operator[](ll index){
		return graph[index];
	}
	size_t size(){return graph.size();}
};

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);

	int N=in();
	ConnectNodeInfo connect(N);
	vector<int> V(N),D(N,-1);
	REP(i,N){
		V[i]=in()-1;
		int k=in();
		REP(j,k){
			int u=in()-1;
			connect.AddDirectionalConnection(V[i],u,1);
		}
	}
	queue<int> Q;
	Q.push(0);
	D[0]=0;
	while(!Q.empty()){
		auto X=Q.front();
		Q.pop();
		for(auto& x:connect[X]){
			if(D[x.first]==-1){
				D[x.first] = D[X]+1;
				Q.push(x.first);
			}
		}
	}
	REP(i,N) out(V[i]+1,D[i]);
	return 0;
}