시간 제한 메모리 제한 제출 정답 맞은 사람 정답 비율
1 초 256 MB 2 2 2 100.000%

문제

Construct an $N \times N$ grid with the following conditions:

  • $2 \leq N \leq 150$
  • Each cell is filled with either 'O' or '.'.
  • There are at least 1700 cells with 'O'.
  • For each tuple of four integers $i, j, k, l$ such that $1 \leq i < j \leq N$ and $1 \leq k < l \leq N$, at least one of the four cells $(i,k)$, $(i,l)$, $(j,k)$, $(j,l)$ is filled with '.'.

입력

There is no input.

출력

The first line should contain an integer $N$. The following $N$ lines should contain $N$ characters each ('O' or '.'), and these $N$ lines describe the grid.

예제 입력 1


						

예제 출력 1

5
.....
.....
..OOO
...O.
..O..

노트

Output for this example satisfies all conditions but the third (number of 'O' in the grid).

채점

  • 예제는 채점하지 않는다.