There is an n*m plot of land, each plot is either overgrown with weeds (represented by 
'W') or empty (represented by 'G'), and now there is a man standing at (1,1), facing 
(1,m), who can move in the following two ways:

1. It takes 1 unit of time to move one grid in the direction facing
2, move down one grid, and reverse the direction of the face (right to left, left to right), 
spend 1 unit of time
Now he wants to know the minimum number of units of time it takes to remove all the weeds (no need to return (1,1))

The first line n, m

The next n rows represent the matrix as a string in each row.

n,m < = 150

An integer in a row represents the answer.

4 5
GWGGW
GGWGG
GWGGG
WGGGG

11