def advent3a(data,dx=3,dy=1):
data = data.splitlines()
x = y = 0
trees = 0
while y < len(data):
if data[y][x%len(data[y])] == "#":
trees += 1
x += dx
y += dy
return trees
def advent3b(data):
z=1
for deltas in ((1, 1), (3, 1), (5, 1), (7, 1), (1, 2)):
z *= advent3a(data, *deltas)
return z