This is:

Arkady Gaidar, “Chuck and Gek”
Chuck − is undoubtedly Chuck − a dime from Charles (Charles).
And Heck − is, respectively, Huck, a reducer from Huckleberry (Heckelberry).
Does anyone doubt?
It is ===

and ah. For example, people who read Gaidar, and not only this story. And familiar facts from the biography of this writer.
Chuk is Vladimir.
Heck is Sergei.
Read the sources, in short.