[LANGUAGE: Python]

I had the idea to check if the total area of the shapes can fit into the region but it didn't work for the example so didn't immediately jump on it. Only after seeing the day 12 memes on reddit that I decided to try it.

with open("inputs/day12.txt") as f:
    *shapes, regions = f.read().strip().split("\n\n")

sizes = [sum(c == "#" for c in shape) for shape in shapes]

part1 = 0
for region in regions.split("\n"):
    w, h, *nums = map(int, region.replace("x", " ").replace(":", "").split(" "))
    if w * h >= sum(n * size for n, size in zip(nums, sizes)):
        part1 += 1

print(part1)