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++: /**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author champon
 */

#include <iostream>
#include <fstream>
#include<bits/stdc++.h>
#define se cout << "test ok" << endl;
#define sp << " " <<
#define enl "\n"
using namespace std;
using ll=long long;
using ld=long double;
ll mod = ll(1e9)+7;
ll inf = ll(1e18);
void bl(bool b, ostream& out=cout){ out << (b ? "Yes" : "No") << endl; }
void bl2(bool b, ostream& out=cout){ out << (b ? "YES" : "NO") << endl; }
template<typename T> inline bool chmax(T &a, T b){ if(a<b){a=b; return true;} return false; }
template<typename T> inline bool chmin(T &a, T b){ if(a>b){a=b; return true;} return false; }
int dx[] = {1, 0, -1, 0, 1, -1, 1, -1};
int dy[] = {0, 1, 0, -1, 1, -1, -1, 1};

#ifndef INCLUDE_DEBUG_HPP
#define INCLUDE_DEBUG_HPP

#include <iostream>
#include <vector>
#include <map>
using namespace std;

namespace dbg {
    using ll = long long;

    class Debug {
    public:
        Debug(){}
        template<typename T>
        void vd(vector<T> vec);
        template<typename T>
        void vd2(vector<vector<T>> vec);
        template<typename T>
        void ad(T *arr, ll n);
        template<typename T, size_t N>
        void ad2(T (&arr)[N], ll n);
        template<typename T>
        void md(T mp);
    };

    template<typename T>
    void Debug::vd(vector<T> vec) {
        for (auto vv : vec) cout << vv << " ";
        cout << endl;
    }

    template<typename T>
    void Debug::vd2(vector<vector<T>> vec) {
        for (auto vv : vec) {
            for (auto vvv : vv) cout << vvv << " ";
            cout << endl;
        }
    }

    template<typename T>
    void Debug::ad(T *arr, ll n) {
        for (int i = 0; i <= n; i++) cout << arr[i] << " ";
        cout << endl;
    }

    template<typename T, size_t N>
    void Debug::ad2(T (&arr)[N], ll n) {
        for (int i = 0; i <= N; i++) for (int j = 0; j <= n; j++) cout << arr[i][j] << " ";
        cout << endl;
    }

    template<typename T>
    void Debug::md(T mp) {
        cout << "key : value" << endl;
        for (auto const &m : mp) cout << m.first << " : " << m.second << endl;
        cout << endl;
    }

}

#endif //INCLUDE_DEBUG_HPP

using dbg::Debug;
Debug debug;

class a {
public:
	void solve(std::istream& in, std::ostream& out) {
	    int n;
	    in >> n;
	    int u, k;
	    vector<vector<int>> g(n);
	    for(int i=0; i<n; i++){
            in >> u >> k;
            --u;
            int v;
            for(int j=0; j<k; j++){
                in >> v;
                g[u].push_back(--v);
            }
	    }

	    queue<int> q;
	    vector<ll> dist(n, inf);
	    q.push(0);
	    dist[0] = 0;
	    while(!q.empty()){
	        int from = q.front();
	        q.pop();
	        for(auto& to : g[from]){
                if(dist[to] > dist[from] + 1){
                    dist[to] = dist[from] + 1;
                    q.push(to);
                }
	        }
	    }

	    for(int i=0; i<n; i++){
	        out << i+1 sp (dist[i]==inf ? -1 : dist[i]) << enl;
	    }
	}
};


int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
	a solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
	solver.solve(in, out);
	return 0;
}

C++: #include<iostream>
#include<vector>
#include<queue>
using namespace std;

int main(){
    int n;
    cin>>n;
    vector<vector<int>> g(n);
    int u,k,v;
    for(int i=0;i<n;++i){
        cin>>u>>k;
        if(k==0)continue;
        for(int j=0;j<k;++j){
            cin>>v;
            g[i].push_back(v-1);
        }
    }
    vector<int> dist(n,-1);
    queue<int> que;
    dist[0]=0;
    que.push(0);
    while(!que.empty()){
        int q=que.front();
        que.pop();
        for(int nv:g[q]){
            if(dist[nv]!=-1)continue;
            dist[nv]=dist[q]+1;
            que.push(nv);
        }
    }
    for(int i=0;i<n;++i){
        cout<<i+1<<" "<<dist[i]<<endl;
        //if(i<n-1)cout<<""<<endl;
    }
    return 0;
}

C++: /*
** BFS
*/

# include <cstdio>
# include <cstring>
# include <queue>
using namespace std;

const int MAX = 100 + 2;
int n, g[MAX][MAX], d[MAX], c[MAX];

void init() {
    scanf("%d", &n);
    memset(g, 0, sizeof(g));
    memset(c, 0, sizeof(c));

    int u, v, k;
    for (int i = 1; i <= n; i++) {
        d[i] = -1;
        scanf("%d%d", &u, &k);
        while (k--) {
            scanf("%d", &v);
            g[u][v] = 1;
        }
    }
}

void bfs() {
    queue<int> q;
    q.push(1);
    c[1] = 1;
    d[1] = 0;

    while (!q.empty()) {
        int v = q.front();
        q.pop();
        for (int i = 1; i <= n; i++) {
            if (g[v][i] == 1 && c[i] == 0) {
                q.push(i);
                c[i] = 1;
                d[i] = d[v] + 1;
            }
        }
    }
}

void solve() {
    init();
    bfs();
    for (int i = 1; i <= n; i++) {
        printf("%d %d\n", i, d[i]);
    }
}

int main() {
    // freopen("infile", "r", stdin);
    // freopen("outfile", "w", stdout);
    solve();
    return 0;
}