100 atcoder#ABC141B. [ABC141B] Tap Dance

[ABC141B] Tap Dance

Score: 200200 points

Problem Statement

Takahashi will do a tap dance. The dance is described by a string SS 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.

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

  • Every character in an odd position (11-st, 33-rd, 55-th, \ldots) is R, U, or D.
  • Every character in an even position (22-nd, 44-th, 66-th, \ldots) is L, U, or D.

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

Constraints

  • SS is a string of length between 11 and 100100 (inclusive).
  • Each character of SS is L, R, U, or D.

Input

Input is given from Standard Input in the following format:

SS

Output

Print Yes if SS is easily playable, and No otherwise.

RUDLUDR
Yes

Every character in an odd position (11-st, 33-rd, 55-th, 77-th) is R, U, or D.

Every character in an even position (22-nd, 44-th, 66-th) is L, U, or D.

Thus, SS is easily playable.

DULL
No

The 33-rd character is not R, U, nor D, so SS is not easily playable.

UUUUUUUUUUUUUUU
Yes
ULURU
No
RDULULDURURLRDULRLR
Yes