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 <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll MOD = 1e9 + 7;
const int inf = 1e9;
const ll INF = 1e18;
const double pi = 3.14159265358979323846;
#define rep(i, n) for (int i = 0; i < n; i++)
using Graph = vector<vector<int>>;
using pint = pair<int, int>;
int dx[4] = { 1, 0, -1, 0 }, dy[4] = { 0, 1, 0, -1 };

int main() {
    int n;
    cin >> n;
    Graph g (n);
    queue<int> q;
    rep (i, n) {
        int a, k;
        cin >> a >> k;
        rep (j, k) {
            int b;
            cin >> b;
            g[a - 1].push_back (b - 1);
        }
    }
    int dist[n] = {};
    rep (i, n) dist[i] = -1;
    dist[0] = 0;
    q.push (0);
    while (!q.empty()) {
        int now = q.front();
        q.pop();
        for (auto p : g[now]) {
            if (dist[p] != -1) continue;
            dist[p] = dist[now] + 1;
            q.push (p);
        }
    }
    rep (i, n) {
        cout << i + 1 << " " << dist[i] << "\n";
    }
}

C++: //
// Created by tattsun on 2017/02/14.
//

#include <iostream>
#include <vector>

#define VERTEX_NUM_MAX 101

using namespace std;
typedef vector<int> Vertex;

int n;
Vertex vs[VERTEX_NUM_MAX];
int ds[VERTEX_NUM_MAX];

void _bfs(vector<int>& targets, int distance) {
    vector<int> next_targets;

    for(auto it = targets.begin(); it != targets.end(); it++) {
        if(ds[*it] == -1) {
            ds[*it] = distance;

            auto& t = vs[*it];
            for(auto itt = t.begin(); itt != t.end(); itt++)
                next_targets.push_back(*itt);
        }
    }

    if(next_targets.empty())
        return;

    _bfs(next_targets, distance+1);
}

void bfs() {
    vector<int> targets;
    targets.push_back(1);

    _bfs(targets, 0);
}

int main() {
    for(int i=0; i<VERTEX_NUM_MAX; i++) {
        ds[i] = -1;
    }

    cin >> n;

    int u, k, p;
    for(int i=1; i<=n; i++) {
        cin >> u >> k;
        for(int j=0; j<k; j++) {
            cin >> p;
            vs[i].push_back(p);
        }
    }

    bfs();

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

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

#define rep(i, a, b) for (int i = (a); i < (int)(b); i++)
#define rrep(i, a, b) for (int i = (a); i >= (int)(b); i--)
#define all(x) (x).begin(), (x).end()
using i32 = int32_t;
using i64 = int64_t;
using f32 = float;
using f64 = double;
using P   = pair<int, int>;

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

template <class T>
void dump_vec(const vector<T>& v) {
    auto len = v.size();
    rep(i, 0, len) {
        cout << v[i] << (i == (int)len - 1 ? "\n" : " ");
    }
}

struct FastIO {
    FastIO() {
        cin.tie(0);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(20);
    }
} FASTIO;

//---------------------------------------------------------------------------------------------------

//---------------------------------------------------------------------------------------------------

signed main() {
    int N;
    cin >> N;
    vector<vector<int>> G(N);
    rep(i, 0, N) {
        int id, k;
        cin >> id >> k;
        id--;
        rep(j, 0, k) {
            int u;
            cin >> u;
            u--;
            G[id].push_back(u);
        }
    }

    const auto inf = 1 << 30;
    vector<int> dist(N, inf);
    dist[0] = 0;
    queue<P> q;
    q.push(make_pair(0, 0));
    while (!q.empty()) {
        auto pi = q.front();
        q.pop();
        auto u = pi.first, cost = pi.second;
        for (auto& to : G[u]) {
            if (chmin(dist[to], cost + 1)) {
                q.push(make_pair(to, dist[to]));
            }
        }
    }

    rep(i, 0, N) {
        cout << i + 1 << " " << (dist[i] == inf ? -1 : dist[i]) << "\n";
    }
}

C++: //
//
//  algoC.cpp - created by us162022
//
#include <iostream>
#include <queue>
using namespace std;
struct Node{
  int u,k,v[99];
  int distance;
};

int main(int argc, char *argv[])
{
  int n;
  Node node[100];
  queue<Node> que;

  cin >> n;

  for(int i=0; i<n; i++){
    cin >> node[i].u >> node[i].k;

    for(int j=0; j<node[i].k; j++)
      cin >> node[i].v[j];

    node[i].distance=-1;
  }

  node[0].distance = 0;
  que.push(node[0]);

  while(!que.empty()){
    Node fro = que.front();

    for(int i=0; i<fro.k; i++){
      int x = fro.v[i]-1;
  
      if(node[x].distance==-1)
	    node[x].distance = fro.distance+1;

      que.push(node[x]);
    }

    que.pop();
  }

  for(int i=0; i<n; i++)
    cout << node[i].u << " " << node[i].distance << endl;

}

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

int A[100][100];//隣接行列
int n;
int D[100];  //訪問状態を保持　距離で

void bfs(int s) {
	queue<int> Q;
	Q.push(s);
	D[s] = 0; 
	while (! Q.empty()) {
		int cur = Q.front();
		Q.pop();
		for (int d=0; d<n; ++d) {
			if (A[cur][d] == 1 && D[d] == -1) {
				D[d] = D[cur]+1;
				Q.push(d);
			}
		}
	}
}

int main() {
	cin >> n;
	int p,q,r;
	for (int i=0; i<n; ++i) {
		cin >> p >> q;
		D[i] = -1; //到達不可能の時-1
		for (int i=0; i<q; ++i) {
			cin >> r;
			A[p-1][r-1] = 1;
		}
	}
	bfs(0);
	for (int i=0; i<n; ++i) {
		cout << i+1 << " " << D[i] << endl;
	}
    return 0;
}