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  1. All Contests
  2. HourRank 7
  3. Paint The Tiles

Paint The Tiles

Nikita has a line of tiles indexed from to . She wants to paint them to match a color configuration, , which is comprised of colors: and .

In one stroke, Nikita can paint or more adjacent tiles a single color. After she finishes painting, each tile should be painted color .

It should be noted that it is not allowed to apply more than stroke on a tile.

Given the required color configuration, find and print the minimum number of strokes required for Nikita to paint all tiles.

Note: In a line of tiles, tiles with the indices and are considered adjacent only if .

Input Format

The first line contains a single integer, , denoting the number of tiles to be painted.
The second line contains a string, , denoting the desired color configuration.

For each character in :

  • If , it means the tile must be painted red.
  • If , it means the tile must be painted blue.

Constraints

Output Format

Print the minimum number of strokes required to paint all tiles in the desired color configuration.

Sample Input 0 

5  
RRRRR

Sample Output 0 

1

Sample Input 1 

5  
RRBRR

Sample Output 1 

3

Sample Input 2 

5  
BRBRB

Sample Output 2 

5

Explanation

Sample Case 0:

Nikita will paint all consecutive tiles red in a single stroke:

Sample Case 1:

Nikita will need strokes to paint all tiles: