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()
}

Python: n = int(input())

m = [[0 for i in range(n)] for j in range(n)]

for i in range(n):
    com = list(map(int, input().split()))
    for j in range(com[1]):
        m[i][com[j+2]-1] = 1

color = ["white" for i in range(n)]

from collections import deque
queue = deque()

d = [-1 for i in range(n)]

def bfs():
    color[0] = "gray"
    d[0] = 0
    queue.append(0)
    while len(queue) != 0:
        u = queue.popleft()
        for i in range(n):
            if m[u][i] and color[i] == "white":
                color[i] = "gray"
                d[i] = d[u] + 1
                queue.append(i)
        color[u] = "black"

bfs()
for i in range(n):
    print(i+1, d[i])

Python: import sys
input = sys.stdin.readline
from collections import deque

N = int(input())
G = [list(map(lambda x: int(x)-1, input().split()))[2:] for _ in range(N)]

D = [-1]*N
q = deque([[0, 0]])
while q:
    cur, dis = q.popleft()
    if D[cur] != -1: continue
    D[cur] = dis
    for nex in G[cur]:
        q.append([nex,dis+1])
for i in range(N):
    print(i+1, D[i])

Python: # -*- coding: utf-8 -*-
"""
Created on Sat Apr  6 11:50:13 2019

@author: Yamazaki Kenichi
"""
from collections import deque

n = int(input())
A = [[]] + [list(map(int,input().split())) for i in range(n)]

#B = [[0 for i in range(n+1)] for i in range(n+1)]
#for i in range(1,n+1):
#    for j in range(A[i][1]):
#        B[i][A[i][j+2]] = 1

T = [[-1, -1] for i in range(n+1)]
T[1][0], T[1][1] = 1, 0
q = deque([1])
def dfs():
    global depth
    while len(q) > 0:
        for i in range(A[q[0]][1]):
            if T[A[q[0]][i+2]][0] == -1:
                q.append(A[q[0]][i+2])
                T[q[-1]][0] = 1
                T[q[-1]][1] = T[q[0]][1] + 1
        q.popleft()
dfs()
for i in range(1,n+1):
    print(i,T[i][1])

Python: from collections import deque
n = int(input())
data = [None]*n
for _ in range(n):
    a,*b = map(int,input().split())
    a -= 1
    data[a] = [i-1 for i in b[1:]]
d = [-1]*n
dq = deque([(0,0)])
while dq:
    p,q = dq.popleft()
    if d[p] == -1:
        d[p] = q
        for i in data[p]:
            dq.append((i,q+1))
for i,j in enumerate(d):
    print(i+1,j)

Python: N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=[0]
d=[0]+[-1]*N
while q:
 u=q.pop(0)
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q+=[v]
for i in range(N):print(i+1,d[i])

Python: N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=[0]
d=[0]+[-1]*N
while q:
 u=q.pop(0)
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q+=[v]
for i in range(N):print(i+1,d[i])

Python: n=int(input())
dic=[[] for i in range(n)]
for i in range(n):
    a=list(map(int,input().split()))
    a=a[2:]
    dic[i]=list(map(lambda x:x-1,a))

from collections import deque
d=deque()
d.append(0) #始点
completed=[False]*n
distance=[999]*n
distance[0]=0
while d:
    now=d.popleft()
    completed[now]=True
    for x in dic[now]: #次の頂点探し
        if completed[x]==False: #その頂点に進んでもよいか
            distance[x]=min(distance[now]+1,distance[x])  #処理
            d.append(x)
for i in range(n):
    if distance[i]==999:
        distance[i]=-1
    print(i+1,distance[i])

Python: n = int(input())
a = [[] for i in range(n)]

for i in range(n):
    v = list(map(int, input().split()))
    u = v[0] - 1
    for j in v[2:]:
        a[u].append(j-1)

d = [-1] * n
isDiscovered = [False] * n

def bfs(x):
    for i in a[x]:
        if not isDiscovered[i]:
            isDiscovered [i] = True
            d[i] = d[x] + 1

d_ = 0
isDiscovered [0] = True
d[0] = 0
bfs(0)

flag = True
while flag:
    flag = False
    for i in range(n):
        if d[i] is d_ :
            flag = True
            bfs(i)
    d_ += 1

for i in range(n):
    print(i+1, d[i])

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
input:
4
1 2 2 4
2 1 4
3 0
4 1 3

output:
1 0
2 1
3 2
4 1
"""

import sys
from collections import deque

UNVISITED, VISITED_IN_QUEUE, POPPED_OUT = 0, 1, 2


def graph_bfs(v_init):
    queue = deque()
    visited[v_init] = VISITED_IN_QUEUE
    distance[v_init] = 0
    queue.appendleft(v_init)

    while queue:
        current = queue.popleft()
        for adj in adj_table[current]:
            if visited[adj] is UNVISITED:
                visited[adj] = VISITED_IN_QUEUE
                distance[adj] = distance[current] + 1
                queue.append(adj)
        visited[current] = POPPED_OUT
    return None


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    v_num = int(_input[0])
    vertices = map(lambda x: x.split(), _input[1:])

    visited = [UNVISITED] * (v_num + 1)
    distance = [-1] * (v_num + 1)

    adj_table = tuple([] for _ in range(v_num + 1))
    for v_info in vertices:
        v_index, adj_num, *adj_list = map(int, v_info)
        # assert len(adj_list) == adj_num
        adj_table[v_index].extend(adj_list)

    graph_bfs(v_init=1)
    for index, v in enumerate(distance[1:], 1):
        print(index, v)