Kerrostaloihin
Kerrostaloihin is a Finnish word meaning into or to apartment buildings. It is the illative plural form of kerrostalo, which refers to a block of flats or a multi-storey residential building. The illative case marks direction or destination, frequently used with verbs of movement or change of residence.
The phrase is used when speaking about moving toward or entering multiple apartment buildings. For example,
Gramatically, kerrostaloihin is formed from kerrostalo with the illative plural suffix, used after verbs of motion
In summary, kerrostaloihin is the illative plural form used to express movement toward or into multiple apartment