output_description: For each vertex $u$, print $id$ and $d$ in a line. $id$ is ID of vertex $u$
  and $d$ is the distance from vertex $1$ to vertex $u$. If there are no path
  from vertex $1$ to vertex $u$, print -1 as the shortest distance. Print in
  order of IDs.
input_description: In the first line, an integer $n$ denoting the number of vertices, is given.
  In the next $n$ lines, adjacent lists of vertex $u$ are given in the following
  format:
  
  $u$ $k$ $v_1$ $v_2$ ... $v_k$
  
  $u$ is ID of the vertex and $k$ denotes its degree.$v_i$ are IDs of vertices
  adjacent to $u$.
problem_description: Breadth First Search
  
  Write a program which reads an directed graph $G = (V, E)$, and finds the
  shortest distance from vertex $1$ to each vertex (the number of edges in the
  shortest path). Vertices are identified by IDs $1, 2, ... n$.
samples: [{"input": "4\n    1 2 2 4\n    2 1 4\n    3 0\n    4 1 3", "output": "1 0\n    2 1\n    3 2\n    4 1"}]