Score : $300$ points
You are given a string $S$.
How many ways are there to choose and underline eight of its characters so that those characters read c
, h
, o
, k
, u
, d
, a
, i
from left to right?
Since the count can be enormous, print it modulo $(10^9 + 7)$.
Input is given from Standard Input in the following format:
$S$
Print the number of ways modulo $(10^9 + 7)$.
chchokudai
3
We have three valid ways:
chchokudai
chchokudai
chchokudai
while the following is invalid:
chchokudai
atcoderrr
0
The answer may be $0$.
chokudaichokudaichokudai
45