In humid climates, people constantly dehumidify their cellars in order to prevent rot and mildew. If the cella?

In humid climates, people constantly dehumidify their cellars in order to prevent rot and mildew. If the cellar in a house (kept at 20oC) has 90.0m2 of floor space and a ceiling height of 2.90m, what is the mass of water that must be removed from it in order to drop the humidity from 90.3 percent to a more reasonable 27.9 percent?