Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Scan()
	num, _ := strconv.Atoi(sc.Text())
	nodes := make(map[int]*node)

	for i := 0; i < num; i++ {
		sc.Scan()
		id, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		nodeNum, _ := strconv.Atoi(sc.Text())
		n := node{id, make([]int, 0), -1}
		for j := 0; j < nodeNum; j++ {
			sc.Scan()
			nid, _ := strconv.Atoi(sc.Text())
			n.nexts = append(n.nexts, nid)
		}
		nodes[id] = &n
	}
	nodes[1].depth = 0

	walk(1, 0, &nodes)
	for i := 1; i < len(nodes)+1; i++ {
		fmt.Printf("%v %v\n", (*nodes[i]).id, (*nodes[i]).depth)
	}
}

var time int
var record [100][100]bool
var q Queue

func walk(nid int, from int, nodes *map[int]*node) {
	q.Enqueue((*nodes)[nid])
	for !q.IsEmpty() {
		n := q.Dequeue().(*node)
		for _, v := range n.nexts {
			n2 := (*nodes)[v]
			if n2.depth != -1 {
				continue
			}
			n2.depth = n.depth + 1
			q.Enqueue((*nodes)[v])
		}
	}
}

type node struct {
	id    int
	nexts []int
	depth int
}

// Queue is Queue
type Queue struct {
	val []interface{}
}

// Enqueue value
func (queue *Queue) Enqueue(val interface{}) {
	queue.val = append(queue.val, val)
}

// Dequeue value
func (queue *Queue) Dequeue() interface{} {
	res := queue.val[0]
	queue.val = queue.val[1:len(queue.val)]
	return res
}

// IsEmpty return true when queue is empty
func (queue *Queue) IsEmpty() bool {
	return len(queue.val) == 0
}

C++: #include "bits/stdc++.h"
#define Rep(i,n) for(int i=0;i<(int)(n);i++)
#define For(i,n1,n2) for(int i=(int)(n1);i<(int)(n2);i++)
#define REP(i,n) for(ll i=0;i<(ll)(n);i++)
#define RREP(i,n) for(ll i=((ll)(n)-1);i>=0;i--)
#define FOR(i,n1,n2) for(ll i=(ll)(n1);i<(ll)(n2);i++)
#define RFOR(i,n1,n2) for(ll i=((ll)(n1)-1);i>=(ll)(n2);i--)
#define all(a)  (a).begin(),(a).end()
#define IOS std::cin.tie(0),std::ios::sync_with_stdio(false)

namespace idaten {

	using namespace std;
	using ll = int_fast64_t;
	using ull = uint_fast64_t;
	using P = std::pair<int64_t, int64_t>;
	template<typename T1, typename T2> inline bool chmin(T1& a, T2 b) { if (a > b) { a = b; return 1; }return 0; }
	template<typename T1, typename T2> inline bool chmax(T1& a, T2 b) { if (a < b) { a = b; return 1; }return 0; }
	template<class Type>struct is_vector : std::false_type {};
	template<class ValueType, class Alloc>struct is_vector<std::vector<ValueType, Alloc>> : std::true_type {};
	template <typename T> inline std::ostream& operator << (std::ostream& out, const std::vector<T>& v) {
		if (v.empty())return out;
		constexpr bool is_vector_v = is_vector<T>::value;
		if (is_vector_v)for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? "\n" : "");
		else for (auto itr = v.begin(); itr != v.end();)out << (*itr), out << ((++itr != v.end()) ? " " : "");
		return out;
	}
	inline void put() {}
	template<class T> inline void put(const T& first) { std::cout << first << "\n"; }
	template<class T, class... N> inline void put(const T& first, const N& ... rest) { std::cout << first << " "; put(rest...); }
	inline void putn() {}
	template<class T, class... N> inline void putn(const T& first, const N& ... rest) { std::cout << first << "\n"; putn(rest...); }

	void solve() {
		IOS;
		int n;
		cin >> n;
		vector<vector<int>> path(n);
		REP(i, n) {
			int u, k;
			cin >> u >> k;
			u--;
			REP(j, k) {
				int v;
				cin >> v;
				v--;
				path[u].push_back(v);
			}
		}
		queue<int> q;
		vector<int> d(n, -1);
		int s = 0;
		d[s] = 0;
		q.push(s);
		while (!q.empty()) {
			int p = q.front();
			q.pop();
			REP(i, path[p].size()) {
				int t = path[p][i];
				if (d[t] < 0) {
					d[t] = d[p] + 1;
					q.push(t);
				}
			}
		}
		REP(i, n) {
			put(i + 1, d[i]);
		}

	}
} // namespace idaten

int main() {
	idaten::solve();
	return 0;
}

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

const int INF = 1e9;

int main() {
  int n;
  cin >> n;

  vector<vector<int> > G(n, vector<int>(n, 0));
  for ( int i = 0; i < n; i++ ) {
    int u, k;
    cin >> u >> k;
    u--;
    for ( int i = 0; i < k; i++ ) {
      int v;
      cin >> v;
      v--;
      G[u][v] = 1;
    }
  }

  queue<int> q;
  vector<int> d(n, -1);
  d[0] = 0;
  q.push(0);
  while ( !q.empty() ) {
    int p = q.front(); q.pop();
    for ( int i = 0; i < n; i++ ) {
      if ( G[p][i] && d[i] == -1 ) {
	q.push(i);
	d[i] = d[p]+1;
      }
    }
  }

  for ( int i = 0; i < n; i++ ) {
    cout << i+1 << " " << d[i] << endl;
  }
  
  return 0;
}