Oof. Sorry to hear that. The motherboard might be possible to save, the way Tico said, though I'd recommend a couple of more steps first to maximize the chances and avoid possible problems in the future: First, if it's installed, remove the BIOS battery as soon as possible, to minimize any electrolysis corrosion, then rinse the board with distilled water to get off any salts or dirt in the flooding water, that otherwise later might absorb moisture from the air and start conducting, then put it to dry according to Tico's instruction.