He says: "I'm renovating my living room and since your flat is the same as mine, I'm wondering, how many rolls of wallpaper did you buy for your living room?"

Neighbour: "I bought 13 rolls!"

After a week the tenant calls his neighbour: "Hey, I also bought 13 rolls of wallpaper, I've covered all the walls and still have 6 rolls left over?!"

Neighbour: " Yeah, I had 6 rolls left over too!"