import functools
import sys
import typing


class Loc(typing.NamedTuple):
    x: int
    y: int


def main() -> int:
    forest_frame = [list(line.strip()) for line in sys.stdin.readlines()]
    frame_width = len(forest_frame[0])
    frame_height = len(forest_frame)

    all_trees_encountered = []

    for slope in [
        Loc(x=1, y=1),
        Loc(x=3, y=1),
        Loc(x=5, y=1),
        Loc(x=7, y=1),
        Loc(x=1, y=2),
    ]:
        loc = Loc(x=0, y=0)

        trees_encountered = 0

        while loc.y <= (frame_height - 1):
            at_loc = forest_frame[loc.y][loc.x]
            if at_loc == "#":
                trees_encountered += 1

            next_x = (loc.x + slope.x) % frame_width
            next_y = loc.y + slope.y
            next_loc = Loc(x=next_x, y=next_y)
            loc = next_loc

        print(
            f"(slope right={slope.x} down={slope.y}) trees encountered: {trees_encountered}"
        )
        all_trees_encountered.append(trees_encountered)

    trees_encountered_product = functools.reduce(
        lambda x, y: x * y, all_trees_encountered
    )
    print(f"trees encountered product: {trees_encountered_product}")
    return 0


if __name__ == "__main__":
    sys.exit(main())