Correct

题外话

/ tí wài huà / 
Strokes

Example

As a Noun

digression

1
Shuō
说
gōu
句
tí
题
wàihuà
外话
  
,
nǐmen
你们
kàn
看
guò
过
zhè
这
běn
本
shū
书
ma
吗
  
?

By the way, have you read the book?