如图 A 中的项链，从第 9 和第 10 个或者第 24 和 第 25 个珠子中间截断，则我们可以收集到 8 个珠子。



图 B 中的项链有白色的珠子，当遇到白色的珠子时，它既可以作为蓝色的珠子看待，也可以作为红色的珠子看待，由收集珠子时的需求决定。包含有白色珠子的项链则会由 r、b 和 w 字符组成的字符串来表示。



请编写一个程序计算从某条项链中能够收集到多少个珠子。-Figure A, the necklace, from 9 and 10 or 24 and the middle cut 25 beads, then we can collect up to 8 beads. Figure B necklace with white beads, white beads when faced with when both can be viewed as blue beads, the beads can also be viewed as red, when the demand by the decision to collect beads. Contains white beads from the necklace will be r, b and w to represent a string of characters. Please write a program to calculate from a necklace of beads to collect the number.