If I am not mistaken // operator is in Python since 2.2... I found this in PEP 238

Here are the changes 2.2 introduces:

A new operator, //, is the floor division operator. (Yes, we know it looks like C++'s comment symbol.) // always performs floor division no matter what the types of its operands are, so 1 // 2 is 0 and 1.0 // 2.0 is also 0.0.

// is always available in Python 2.2; you don't need to enable it using a __future__ statement. 

thanks for helping me improve my code! :) does the // mean that python3 is used?