8459: Hoof, Paper, Scissors

The rules of "Hoof, Paper, Scissors" are simple. Two cows play against each-other. They both count to three and then each simultaneously makes a gesture that represents either a hoof, a piece of paper, or a pair of scissors. Hoof beats scissors (since a hoof can smash a pair of scissors), scissors beats paper (since scissors can cut paper), and paper beats hoof (since the hoof can get a papercut). For example, if the first cow makes a "hoof" gesture and the second a "paper" gesture, then the second cow wins. Of course, it is also possible to tie, if both cows make the same gesture.

Farmer John wants to play against his prize cow, Bessie, at NN games of "Hoof, Paper, Scissors" (1≤N≤100,0001≤N≤100,000). Bessie, being an expert at the game, can predict each of FJ's gestures before he makes it. Unfortunately, Bessie, being a cow, is also very lazy. As a result, she tends to play the same gesture multiple times in a row. In fact, she is only willing to switch gestures at most once over the entire set of games. For example, she might play "hoof" for the first xx games, then switch to "paper" for the remaining N−xN−x games.

Given the sequence of gestures FJ will be playing, please determine the maximum number of games that Bessie can win.

你可能玩过“石头，剪刀，布”，这个游戏在奶牛中同样流行，不过它的名字变成了“蹄子，剪刀，布”。

“蹄子，剪刀，布”和“石头，剪刀，布”的规则十分类似，两只奶牛数到三，然后出一个代表蹄子，剪刀或布的手势。蹄子胜过剪刀，剪刀胜过布，布胜过蹄子。特别地，如果两只奶牛的手势相同，则视为平局。

现在 FJ 和 Bassie 要进行 $N$ 轮对抗。Bassie 已经预测了 FJ 每一轮要出的手势。然而 Bassie 很懒，她最多只想变换一次手势。

现在请你帮 Bassie 求出她最多能赢多少轮。

第一行输入一个整数 N（1≤N≤105）。

接下来 N 行，每行一个字母，代表 FJ 这一轮出的手势。H 代表蹄子（Hoof），S 代表剪刀（Scissors），P 代表布（Paper）。