Go: package main

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

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, 0, n)
	for i := 0; i < n; i++ {
		ds = append(ds, -1)
	}

	q := make([]int, 0, n)
	q = append(q, 0)
	ds[0] = 0

	for len(q) > 0 {
		i := pop(&q)
		for _, v := range vecs[i] {
			if ds[v] == -1 {
				ds[v] = ds[i]+1
				q = append(q, v)
			}
		}
	}

	for i, d := range ds {
		fmt.Fprintln(w, i+1, d)
	}

	w.Flush()
}

func pop(q *[]int) int {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define fi first
#define se second
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vl>;
using pl=pair<ll,ll>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[4]={1,0,-1,0};
const ll dx[4]={0,-1,0,1};
vvl G;
queue<ll> que;
void BFS(ll v,vl &dist){
    dist[v]=0;
    que.push(v);
    while(que.size()){
        ll v=que.front();
        que.pop();
        for(auto nv:G[v]){
            if(dist[nv]>dist[v]+1){
                dist[nv]=dist[v]+1;
                que.push(nv);
            }
        }
    }
}
int main(){
    ll N;cin>>N;
    vl id(N);
    G=vvl(N,vl());
    rep(i,N){
        cin>>id[i];
        ll k;cin>>k;
        rep(j,k){
            ll a;cin>>a;
            G[i].push_back(a-1);
        }
    }
    vl dist(N,INF);
    BFS(0,dist);
    vector<pl> ans(N);
    rep(i,N){
        ans[i].fi=id[i],ans[i].se=dist[i];
        if(ans[i].se==INF)ans[i].se=-1;
    }
    sort(all(ans));
    rep(i,N)cout<<ans[i].fi<<" "<<ans[i].se<<endl;
    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <map>
#include <numeric>
#include <string>
#include <cmath>
#include <iomanip>
#include <string>
#include <queue>
#include <list>
#include <stack>

typedef long long ll;
using namespace std;
const int mod = 1000000007;

void bfs(int node);
vector< vector<int> > Adj(100, vector<int>(100));
vector<int> dist(100, -1);
int n;

int main() {

    // input
    cin >> n;
    for (int i = 0; i < n; i++) {
        int u, k; cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v; cin >> v; v--;
            Adj[i].push_back(v);
        }
    }

    dist[0] = 0;
    bfs(0);

    for (int i = 0; i < n; i++) {
        cout << i + 1 << ' ' << dist[i] << '\n';
    }

}

void bfs(int node) {

    queue<int> q;
    q.push(node);

    while (!q.empty()) {
        int cur = q.front();
        q.pop();
        for (auto v : Adj[cur]) {
            // visited
            if (dist[v] != -1) {
                continue;
            }
            // not visited
            else {
                dist[v] = dist[cur] + 1;
                q.push(v);
            }
        }
    }

}

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

#define MAX 100
static const int WHITE = 0; // not visit
static const int GRAY = 1; // visited
static const int BLACK = 2; // searched

int n;
int M[MAX][MAX] = { 0 };
int distance[MAX] = { 0 }; // ?????????????§??????????????????¢
int v_states[MAX] = { WHITE };


void breadthFirstSearch() {
	queue<int> vertices;

	vertices.push(0); // ?§????
	while (!vertices.empty()) {
		int u = vertices.front();
		v_states[u] = GRAY;
		vertices.pop();
		bool is_connected = false;
		for (int v = 0; v < n; v++) {
			if (M[u][v] == 1 && v_states[v] == WHITE) {
				::distance[v] = ::distance[u] + 1;
				vertices.push(v);
				v_states[v] = GRAY;
			}
		}
	}
	return;
}

int main() {
	cin >> n;

	for (int i = 0; i < n; i++) {
		int k, u;
		cin >> u >> k;
		u--;
		for (int j = 0; j < k; j++) {
			int v;
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}
	breadthFirstSearch();
	for (int i = 0; i < n; i++) {
		if (i && v_states[i] == WHITE) {
			::distance[i] = -1;
		}
		cout << i + 1 << ' ' << ::distance[i] << endl;
	}

	return 0;

}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = 1001001001;
const int MOD = 1000000007;

template <typename T>
void print(const T &v);

vector<int> dist(105, INF);
vector<int> grid[105];
int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++)
        {
            int v;
            cin >> v;
            grid[u].push_back(v);
        }
    }
    queue<int> qe;
    qe.push(1);
    dist[1] = 0;

    while (!qe.empty())
    {
        int now = qe.front();
        qe.pop();
        for (int next : grid[now])
        {
            if (dist[next] <= dist[now] + 1)
            {
                continue;
            }
            if (dist[next] != INF)
            {
                dist[next] = dist[now] + 1;
                continue;
            }
            else
            {
                dist[next] = dist[now] + 1;
            }
            qe.push(next);
        }
    }
    for (int i = 1; i <= n; i++)
    {
        if (dist[i] != INF)
        {
            cout << i << ' ' << dist[i] << endl;
        }
        else
        {
            cout << i << ' ' << -1 << endl;
        }
    }
    return 0;
}

// Use For Debug
template <typename T>
void print(T const &v)
{
    for (int i = 0; i < v.size(); i++)
    {
        if (i)
            cout << ' ';
        cout << v[i];
    }
    cout << endl;
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
// #define int long long

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

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define RREP(i, n) for (int i = (n); i >= 0; --i)
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define RFOR(i, a, b) for (int i = (a); i >= (b); --i)
#define ALL(v) (v).begin(), (v).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" \
                      << " " << __FILE__ << endl;

typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<vi> vvi;
typedef pair<int, int> pii;

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N;
    cin >> N;
    vvi g(N);
    REP(i, N) {
        int u, k;
        cin >> u >> k;
        u--;
        vi v(k);
        REP(j, k) {
            int t;
            cin >> t;
            t--;
            v[j] = t;
        };

        g[u] = v;
    }

    vi dist(N, -1);
    dist[0] = 0;
    queue<int> q;
    q.push(0);

    while (!q.empty())
    {
        int v = q.front();
        q.pop();

        for (int nv : g[v]) {
            if (dist[nv] == -1) q.push(nv);
            if (dist[nv] == -1) dist[nv] = dist[v] + 1;
            else dist[nv] = min(dist[nv], dist[v] + 1);
        }
    }

    REP(i, N) {
        cout << i+1 << " " << dist[i] << endl;
    }
    
    return 0;
}