Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func stringifyArray(arr []int) string {
	return strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]")
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, &g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

func fillDistancesByBreadthFirstSearch(g *DirectedGraph, startNode *DirectedGraphNode) {
	startNode.visited = true
	startNode.d = 0

	queue := Queue{}
	queue.enqueue(startNode)
	for !queue.isEmpty() {
		u := queue.dequeue().node
		for _, adjacent := range u.adjacents {
			if !adjacent.visited {
				adjacent.visited = true
				adjacent.d = u.d + 1
				adjacent.parent = u
				queue.enqueue(adjacent)
			}
		}
		u.visited = true
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	// fmt.Println(g)
	fillDistancesByBreadthFirstSearch(g, &g.nodes[1])
	// fmt.Println(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		distance := node.d
		if distance == infty {
			distance = -1
		}
		fmt.Println(node.key, distance)
	}
}

Python: N= int(input())
E = [input().split()[2:] for _ in range(N)]
Q = [0]
L = [0] + [-1]*N
frag = [1] + [0]*N
def func(ide):
    global Q
    for i in E[ide]:
        i = int(i) - 1
        if frag[i] != 1:frag[i] = 1;L[i] = L[ide] +1 ;Q.append(i)
        else:return

while Q:top = Q[0];func(top);del Q[0]

for i in range(N):print(i + 1 ,int(L[i]))

Python: from queue import Queue

n = int(input())
A = [[0 for i in range(n)] for j in range(n)]
d = [-1] * n

for i in range(n):
    u, k, *v = list(map(int, input().split()))
    for j in v:
        A[int(u)-1][int(j)-1] = 1

q = Queue()
q.put(0)
d[0] = 0

while not q.empty():

    u = q.get()

    for v in range(n):

        if A[u][v] == 1 and d[v] == -1:
            q.put(v)
            d[v] = d[u] + 1

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

Python: from collections import deque

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

class Node:
  def __init__(self, id, ck):
    self.id = id
    self.ck = ck
    self.depth = -1

  def __str__(self):
    return '{} {}'.format(self.id, self.depth)

class Graph:
  def __init__(self):
    self.map = {}

  def get(self, id):
    return self.map[id]

  def set(self, id, ck):
    self.map[id] = Node(id, ck)

  def bfs(self):
    root = self.get(1)
    root.depth = 0
    queue = deque()
    queue.append(root)
    while(len(queue) > 0):
      node = queue.popleft()
      for id in node.ck:
        target = self.get(id)
        if target.depth != -1: continue
        target.depth = node.depth + 1
        queue.append(target)

  def __str__(self):
    return '\n'.join(map(str, [self.get(i + 1) for i in range(len(self.map))]))

graph = Graph()
for data in adj:
  id = data[0]
  ck = data[2:]
  graph.set(id, ck)

graph.bfs()
print(graph)

Python: n = int(input())
Adj = [[0 for i in range(n)] for i in range(n)]
 
for i in range(n):
    u = list(map(int, input().split()))
    if u[1] > 0:
        for i in u[2: 2 + u[1]]:
            Adj[u[0] - 1][i - 1] = 1
 
color = [0] * n
d = [-1] * n
import queue
Q = queue.Queue()

color[0] = 1
d[0] = 0
Q.put(1)
while not Q.empty():
    u = Q.get()
    for v in range(1, n+1):
        if Adj[u-1][v-1] == 1 and color[v-1] == 0:
            color[v-1] = 1
            d[v-1] = d[u-1] + 1
            Q.put(v)
    color[u-1] = 2

for i in range(n):
    print("{} {}".format(i + 1, d[i]))

Python: n = int(input())

adj = [None]
for i in range(n):
    adj_i = list(map(int, input().split()[2:]))
    adj.append(adj_i)

isSearched = [None] + [False] * n

distance = [None] + [-1] * n

def bfs(u):
    d = 0
    isSearched[u] = True
    distance[u] = d
    edge = [u]
    while edge:
        q = list(edge)
        edge = []
        d += 1
        for c_e in q:
            for n_e in adj[c_e]:
                if not isSearched[n_e]:
                    isSearched[n_e] = True
                    edge.append(n_e)
                    distance[n_e] = d


bfs(1)

for i, x in enumerate(distance[1:], start=1):
    print(i, x)

Python: #Breadth First Search
n=int(input())
V=[]
a=[1]
for i in range(n):
    V.append([int(i) for i in input().split()])
    a.append(0)
V=sorted(V,key=lambda x:x[0])
print('1 0')
d=1
c=0
w=[0]
p=[]
while c<n and w!=[]:
    i=0
    y=[]
 #   print(c)
    while c<n and i<len(w):
        j=2
        while j<2+V[w[i]][1] and c<n:
            if a[V[w[i]][j]-1]==0:
        #        print(a)
                a[V[w[i]][j]-1]=1
                p.append([V[w[i]][j],d])
                c+=1
                y.append(V[w[i]][j]-1)
            j+=1
        i+=1
    w=y
    d+=1
p=sorted(p, key=lambda x:x[0])
#print(p)
i=2
j=0
while i <=n and j<len(p):
    while p[j][0]>i:
        print(str(i) +" -1")
        i+=1
    print(str(p[j][0])+" "+str(p[j][1]))
    i+=1
    j+=1
while i<=n:
    print(str(i)+" -1")
    i+=1

Python: def bfs(G, s):
    d = {key: -1 for key in G.keys()}
    d[s] = 0
    Q = [s]
    while len(Q) > 0:
        u = Q.pop(0)
        for v in G[u]:
            if d[v] < 0:
                d[v] = d[u] + 1
                Q.append(v)

    return d


if __name__ == '__main__':
    G = {}
    n = int(input())
    for _ in range(n):
        tmp = list(map(int, input().split()))
        u = tmp.pop(0)
        k = tmp.pop(0)
        G[u] = tmp
    d = bfs(G, 1)
    for node in G:
        print('{0} {1} '.format(node, d[node]))

Python: import queue

n = int(input())
graph = {}
for _ in range(n):
  i = list(map(int,input().split()))
  graph[i[0]] = i[2:]

dist = [-1 for i in range(n)]
todo = queue.Queue()
seen = set()

dist[0] = 0
todo.put(1)

while (not todo.empty()):
  now = todo.get()
  for nx in graph[now]:
    if (dist[nx-1] != -1):
      continue
    dist[nx-1] = dist[now-1] + 1
    todo.put(nx)

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

Python: from collections import deque

n = int(input())
adj = [[]]
for i in range(n):
    adj.append(list(map(int, input().split()))[2:])

ans = [-1]*(n+1)
ans[1] = 0

q = deque([1])
visited = [False] * (n+1)
visited[1] = True

while q:
    x = q.popleft()
    for y in adj[x]:
        if visited[y] == False:
            q.append(y)
            ans[y] = ans[x]+1
            visited[y] = True

for j in range(1, n+1):
    print(j, ans[j])