because it contains a space at the end.

Even though you say there is "no loop", you need to understand that your sum() isn't magic - it is doing essentially the exact same thing as a loop; it is performing all of those (many) area calculations inside the () and then summing them.

If I tell you, for example, "add all the areas in the board" and "for each area in the board, add it to the total" - are these 2 fundamentally different algorithms? No! The 2nd command obviously has a "for loop" in its syntax, but the 1st command has the exact same calculations also!

If you're struggling still, forget about coding/loops/etc and go back to basics - try to solve this away from your computer, as if it were a puzzle on paper.

Read some of the many posts below asking the same.

Print the input: https://docs.codewars.com/training/troubleshooting/#print-input