
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.
Sample Input 1RUDLUDR
Sample Output 1Yes
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.
Sample Input 2DULL
Sample Output 2No
The 3-rd character is not R, U, nor D, so S is not easily playable.
Sample Input 3UUUUUUUUUUUUUUU
Sample Output 3Yes
Sample Input 4ULURU
Sample Output 4No
Sample Input 5RDULULDURURLRDULRLR
Sample Output 5Yes
