题目描述
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 $1, 2, ... n$.
Constraints
- $1 \leq n \leq 100$
Input
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 $u$.
Output
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.
Example
Input
4
1 2 2 4
2 1 4
3 0
4 1 3
Output
1 0
2 1
3 2
4 1
输入格式
见题面
输出格式
见题面