Problem C: Maze

## Problem C: Maze

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 488  Solved: 182
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## Description

Yuki is a careless girl and she is designing mazes.

A maze consists of $$n$$ rooms and $$m$$ passageways. The rooms are numbered from $$1$$ to $$n$$ and all the passageways are unidirectional, that is the passageway from room $$u$$ to $$v$$ cannot be passed from room $$v$$ to $$u$$. Besides, to avoid tourists being trapped in the maze, all the rooms should be connected, that is for every pair of integers $$(u,v)$$ such that $$1\leq u,v\leq n,u\neq v$$, there should be a path from room $$u$$ to room $$v$$.

Yuki has already designed a "maze". However, due to her carelessness, you need to check whether the maze she designed is a real maze, that is all the rooms in her maze are connected.

## Input

The first line contains two integers: $$n$$ and $$m$$ $$(1\leq n,m\leq 200\ 000)$$ --- the number of rooms and passageways in the maze.

Each of the next $$m$$ lines contains two integers: $$u$$ and $$v$$ $$(1 \leq u,\ v\leq n)$$, meaning that there is a unidirectional passageway from room $$u$$ to room $$v$$.

## Output

If all the rooms in the maze are connected, print “Bravo” (without quotation).

Otherwise print “ovarB” (without quotation).

## Sample Input

3 3
1 2
2 3
3 2

## Sample Output

ovarB

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