With accent marks:
Как ау́кнется, так и откли́кнется.
What goes around comes around.
As you treat others, so they will treat you.
This proverb is hard to translate literally. "Аукнется" comes from the sound "ау" that Russian people use to find each other in a forest. "Аукнется" is only used in this proverb, you don't find this word anywhere else. So a close to literal translation can be as follows: as you say "ау", you will receive the same response back.
Other Russian proverbs
Live for a century, learn for a century, but die being a fool anyway.
Being a guest is good, but being at home is better.
A holy place is never empty.
With whom you are friends with, from them you will learn.
Don't bring your set of rules in a foreign monastery
A bad example is contagious.
A wolf is fed by his legs
Get your sleigh ready in summer and your (horse-drawn) cart in winter.