B - Tap Dance

Score: $200$ points

Problem Statement

Takahashi will do a tap dance. The dance is described by a string $S$ where each character is L, R, U, or D. These characters indicate the positions on which Takahashi should step. He will follow these instructions one by one in order, starting with the first character.

$S$ is said to be easily playable if and only if it satisfies both of the following conditions:

• Every character in an odd position ($1$-st, $3$-rd, $5$-th, $\ldots$) is R, U, or D.
• Every character in an even position ($2$-nd, $4$-th, $6$-th, $\ldots$) is L, U, or D.

Your task is to print Yes if $S$ is easily playable, and No otherwise.

Constraints

• $S$ is a string of length between $1$ and $100$ (inclusive).
• Each character of $S$ is L, R, U, or D.

Input

Input is given from Standard Input in the following format:

$S$

Output

Print Yes if $S$ is easily playable, and No otherwise.

RUDLUDR

Yes

Every character in an odd position ($1$-st, $3$-rd, $5$-th, $7$-th) is R, U, or D.

Every character in an even position ($2$-nd, $4$-th, $6$-th) is L, U, or D.

Thus, $S$ is easily playable.

DULL

No

The $3$-rd character is not R, U, nor D, so $S$ is not easily playable.

UUUUUUUUUUUUUUU

Yes

ULURU

No

RDULULDURURLRDULRLR

Yes