Problem B
Delft Distance
CC BYSA 3.0 by Michiel1972 on Wikipedia
Since you are already late for the contest start, you need to find a shortest path from your hotel to the contest site. Fortunately, you have a map of the city. See Figure 1 for an example.
Input
The input consists of:

One line with two integers $h$ and $w$ ($1 \leq h,w \leq 700$), the number of rows and the number of columns of buildings shown on the map of the city.

$h$ lines, each with $w$ characters which are either ‘O’ (for round towers) or ‘X’ (for square buildings) describing the shapes of the buildings.
The map is oriented with the north side up.
Output
Output the length of a shortest path from the northwest corner to the southeast corner of Delft in metres. Your answer may have a relative or absolute error of at most $10^{6}$.
Sample Input 1  Sample Output 1 

3 5 XOOXO OXOXO XXXXO 
71.4159265359 
Sample Input 2  Sample Output 2 

1 4 XOOX 
45.7079632679 