Codeforces Round 124 (Div. 2)
D
Infinite Maze
Codeforces
未评级
原题
← CE →
翻译中…

We've got a rectangular $*n* × *m*$-cell maze. Each cell is either passable, or is a wall (impassable). A little boy found the maze and cyclically tiled a plane with it so that the plane became an infinite maze. Now on this plane cell $(*x*, *y*)$ is a wall if and only if cell image is a wall.

翻译中…

In this problem image is a remainder of dividing number $*a*$ by number $*b*$.

翻译中…

The little boy stood at some cell on the plane and he wondered whether he can walk infinitely far away from his starting position. From cell $(*x*, *y*)$ he can go to one of the following cells: $(*x*, *y* - 1)$, $(*x*, *y* + 1)$, $(*x* - 1, *y*)$ and $(*x* + 1, *y*)$, provided that the cell he goes to is not a wall.

翻译中…

Input

翻译中…

The first line contains two space-separated integers $*n*$ and $*m*$ ($1 ≤ *n*, *m* ≤ 1500$) — the height and the width of the maze that the boy used to cyclically tile the plane.

翻译中…

Each of the next $*n*$ lines contains $*m*$ characters — the description of the labyrinth. Each character is either a "#", that marks a wall, a ".", that marks a passable cell, or an "S", that marks the little boy's starting point.

翻译中…

The starting point is a passable cell. It is guaranteed that character "S" occurs exactly once in the input.

翻译中…

Output

翻译中…

Print "Yes" (without the quotes), if the little boy can walk infinitely far from the starting point. Otherwise, print "No" (without the quotes).

翻译中…

Note

翻译中…

In the first sample the little boy can go up for infinitely long as there is a "clear path" that goes vertically. He just needs to repeat the following steps infinitely: up, up, left, up, up, right, up.

翻译中…

In the second sample the vertical path is blocked. The path to the left doesn't work, too — the next "copy" of the maze traps the boy.

翻译中…

样例

Input #1
5 4
##.#
##S#
#..#
#.##
#..#
Output #1
Yes
InputCopy OutputCopy
Input #2
5 4
##.#
##S#
#..#
..#.
#.##
Output #2
No
InputCopy OutputCopy
题目信息
题号
197D
时间限制
2 s
内存限制
256 MB

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。