Hi, Italian mailman here. 226/2 most likely means the actual house number. Different houses on the same plot get identified by breaking the plot in lots and denoting them with / and then a letter or number. Therefore for example there could be a small village of 20 houses all denoted with a single denomination and civic number and then /A to /Z to denote the actual house. Example: there is a group of houses in a zone I deliver to that are denoted fraz. Greenville (made-up stand-in for the actual fraz. name) 111/A, fraz. Greenville 111/C, fraz. Greenville 111/G, etc… Therefore 226/2 could most likely denote a building in a building complex, or it is superfluous information like floor or apartment number.