Complement of a regular expression

Question

Question.

Write a regular expression for the languages:

1. all words in $\{a,b,c\}^{*}$ in which $a$ instance is followed by a sequence of at least two $c's$
2. The complement language of $1$

Attempt.

1. $\,\,\,\,r=(b+c+accc^* )^*$

But I'm not sure how to write regular expression of the complement.