https://github.com/Alvant/AdvancedPython/tree/feature/l8/labs/lab08 1, 2, 3; 3 -> 1, 1, 1, 2, 2, 2, 3, 3, 3
https://github.com/Alvant/AdvancedPython/tree/feature/l8/labs/lab08
1, 2, 3; 3 -> 1, 1, 1, 2, 2, 2, 3, 3, 3