1. 每条项链由N个随机排列的红色、白色和蓝色的珠子组成（3<=N<=350）

2. 参与者从项链的某处将它截断拉直；接着从一端向另外一端收集同颜色的珠子，直到碰到一个不同颜色的珠子为止；然后再从另外一端做同样的操作。(一端收集的珠子颜色可以不同于另一端的。)

3. 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。

4. 想办法找到一个截断项链的位置，能够尽量多地收集到同色的珠子，胜出者可免费获得珍珠项链一条。

现在请大家帮忙，编写一段程序，计算从某条项链中最多能够收集到多少个珠子，下面的例子展示了两条 N=29 时的项链：(1. Each necklace consists of N randomly arranged red, white and blue beads (3<=N<=350).



2. Participants cut and straighten the necklace somewhere; then collect the same color beads from one end to the other until they meet a different color bead; and then do the same thing from the other end. The color of beads collected at one end can be different from that collected at the other end. )



3. When encountering white beads, they can be viewed as either blue beads or red beads, depending on the needs of collecting beads.



4. Find a place to cut off the necklace and collect as many pearls of the same color as possible. The winner can get a pearl necklace free of charge.



Now please help me to write a program to calculate how many beads can be collected from a necklace. The following examples show two necklaces when N = 29:)