A - Alternately /

### 問題文

N 人が一列に並んでいます。列の状態は長さ N の文字列 S で与えられ、前から i 番目の人は Si 文字目が M のとき男性、F のとき女性です。

### 制約

• 1 \leq N \leq 100
• N は整数である
• SM および F のみからなる長さ N の文字列である

### 入力

N
S


### 入力例 1

6
MFMFMF


### 出力例 1

Yes


### 入力例 2

9
FMFMMFMFM


### 出力例 2

No


### 入力例 3

1
F


### 出力例 3

Yes


Score : 100 points

### Problem Statement

There is a row of N people. They are described by a string S of length N. The i-th person from the front is male if the i-th character of S is M, and female if it is F.

Determine whether the men and women are alternating.

It is said that the men and women are alternating if and only if there is no position where two men or two women are adjacent.

### Constraints

• 1 \leq N \leq 100
• N is an integer.
• S is a string of length N consisting of M and F.

### Input

The input is given from Standard Input in the following format:

N
S


### Output

Print Yes if the men and women are alternating, and No otherwise.

### Sample Input 1

6
MFMFMF


### Sample Output 1

Yes


There is no position where two men or two women are adjacent, so the men and women are alternating.

### Sample Input 2

9
FMFMMFMFM


### Sample Output 2

No


### Sample Input 3

1
F


### Sample Output 3

Yes