Score : 300 points
There are N stones arranged in a row. Every stone is painted white or black.
A string S represents the color of the stones. The i-th stone from the left is white if the i-th character of S is .
, and the stone is black if the character is #
.
Takahashi wants to change the colors of some stones to black or white so that there will be no white stone immediately to the right of a black stone. Find the minimum number of stones that needs to be recolored.
.
and #
.Input is given from Standard Input in the following format:
N S
Print the minimum number of stones that needs to be recolored.
3 #.#
1
It is enough to change the color of the first stone to white.
5 #.##.
2
9 .........
0