Lemon Game

Woohyun likes to play "Lemon Game". This game's rule is the following:

1. At first, there are $N$ lemons in a row, where a number $A_i$ is written on $i$-th lemon. $A_i$ is either $1$ or $2$.
2. Choose a segment of lemons where the sum of numbers written on them is $3$. Remove every lemon in that segment.
3. Do the above operation some number of times. (Possibly none)

The figure below shows one example of Lemon Game.

Determine if every lemon can be removed.

The input is given in the following format:

$N$ $A_1 \ A_2 \ \cdots \ A_N$

Output one line: print Yes if every lemon can be removed, and print No otherwise.

• $1 \le N \le 200\ 000$.
• $1 \le A_i \le 2$ ().