Catsitting with obstacles

Axel asked me to feed his cats while he was on a business trip. Well, no problem, but I asked him for fool-proof instructions. He was prepared for that, and indeed, he had some PowerPoint slides on “feeding fierce beasts”. However, I was too stupid to understand the description where his flat is. He had said something about the second entrance on the right, but in fact it was ambiguous depending on the way you counted. I was able to enter the wrong house with one key (the houses in that estate are all the same), but of course not the flat. On the phone, Axel finally realised what was going wrong and sent me to the right door.