116. Diverse String
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

You consider a string to be a diverse string if every pair of adjacent characters are different. For example coderams is a diverse string, while hello is not.

Given a string, figure out whether or not it is a diverse string.

Input

The only line of input contains a single string, not containing spaces.

Output

If the string is a diverse string, output "YES" (no quotes). Otherwise, output "NO" (no quotes).

Examples
Input
coderamsclub
Output
YES
Input
helloworld
Output
NO