5198：Strange Class

In Vivid’s school, there is a strange class(SC). In SC, the students’ names are very strange. They are in the same format: $a^{n}b^{n}c^{n}$(a,b,c must not be the same with each other). For example studens whose names are“abc”,”ddppqq” are in SC, however studens whose names are “aaa”,“ab”,”ddppqqq” are not in SC.
Vivid makes friends with so many students, he wants to know who are in SC.

There are multiple test cases (about 10), each case will give a string S which is the name of Vivid’s friend in a single line.
Please process to the end of file.

[Technical Specification]

$1 \leq |S| \leq 10$.

|S| indicates the length of S.

S only contains lowercase letter.

For each case, output YES if Vivid’s friend is the student of SC, otherwise output NO.