athe literal a (9710 / 1418 / 6116) (case sensitive)
.{3,}any character (except for line terminators), repeated at least 3 times
zthe literal z (12210 / 1728 / 7A16) (case sensitive)
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string