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F. Elementary!
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
Input

The input consists of a single string of uppercase letters A-Z. The length of the string is between 1 and 10 characters, inclusive.

Output

Output "YES" or "NO".

Examples
Input
GENIUS
Output
YES
Input
DOCTOR
Output
NO
Input
IRENE
Output
YES
Input
MARY
Output
NO
Input
SMARTPHONE
Output
NO
Input
REVOLVER
Output
YES
Input
HOLMES
Output
NO
Input
WATSON
Output
YES