Score : $100$ points

问题陈述

高桥计划吃 $N$ 道菜。

他计划吃的第 $i$ 道菜如果是甜的，那么 $S_i =$ 甜的；如果是咸的，那么 $S_i =$ 咸的。

如果他连续吃两道甜菜，他会感觉恶心，无法再吃任何菜。

确定他是否能吃完所有菜。

以上为大语言模型 kimi 翻译，仅供参考。

Problem Statement

Takahashi is planning to eat $N$ dishes.

The $i$-th dish he plans to eat is sweet if $S_i =$ sweet, and salty if $S_i =$ salty.

If he eats two sweet dishes consecutively, he will feel sick and be unable to eat any more dishes.

Determine whether he can eat all the dishes.

Constraints

• $N$ is an integer between $1$ and $100$, inclusive.
• Each $S_i$ is sweet or salty.

Input

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

$N$

$S_1$

$S_2$

$\vdots$

$S_N$

Output

Print Yes if Takahashi can eat all the dishes, and No otherwise.

Sample Input 1

5
salty
sweet
salty
salty
sweet

Sample Output 1

Yes

He will not eat two sweet dishes consecutively, so he can eat all the dishes without feeling sick.

Sample Input 2

4
sweet
salty
sweet
sweet

Sample Output 2

Yes

He will feel sick but can still eat all the dishes.

Sample Input 3

6
salty
sweet
sweet
salty
sweet
sweet

Sample Output 3

No

He feels sick when eating the 3rd dish and cannot eat the 4th and subsequent dishes.