NORTH = "^"
SOUTH = "v"
WEST = "<"
EAST = ">"

class Santa:
    def __init__(self, visits): # visits is a ref
        self.pos = [0,0]
        self.visits = visits
        self.visits.add((self.pos[0], self.pos[1]))

    def move(self, d):
        if d == NORTH:
            self.pos[1] += 1
        if d == SOUTH:
            self.pos[1] -= 1
        if d == WEST:
            self.pos[0] -= 1
        if d == EAST:
            self.pos[0] += 1

    def visit(self, d):
        self.move(d)
        self.visits.add((self.pos[0], self.pos[1]))

def visit(l):
    visits = set()

    robo = Santa(visits)
    santa = Santa(visits)
    for i,c in enumerate(l):
        if i%2 == 0:
            santa.visit(c)
        else:
            robo.visit(c)

    return len(visits)


def test():
    assert visit("^v") == 3
    assert visit("^>v<") == 3
    assert visit("^v^v^v^v^v") == 11

def solution():
    with open("in2") as puzzle:
        l = puzzle.read()
        return visit(l)

if __name__ == "__main__":
    print(f"Houses: {solution()}")