from pprint import pprint

with open("data.txt", "r", encoding="utf-8") as f:
	data = [x.rstrip() for x in f]

def traverse(tx, ty):
	x = y = 0
	max_x = len(data[0])
	max_y = len(data) - 1
	trees = 0

	while True:
		x += tx
		xi = x % max_x
		y += ty

		if y > max_y:
			return trees

		assert data[y][xi] in (".", "#")
		if data[y][xi] == "#":
			trees += 1

trees = 1
for x in ((1, 1), (3, 1), (5, 1), (7, 1), (1, 2)):
	z = traverse(*x)
	print(f"The toboggan encountered {z} trees.")
	trees *= z

print(f"Sum: {trees}")