def score(state, offset):
    r = 0
    for i in range(len(state)):
        if state[i] == "#":
            r += i + offset
    return r


def solve(data, target_i):
    state = None
    map = {}
    for line in data.splitlines():
        if "initial state" in line:
            _, rest = line.split(":")
            state = rest.strip()
        if "=>" in line:
            lhs, rhs = line.split(" => ")
            assert lhs not in map
            map[lhs] = rhs

    assert state is not None
    seen = {}
    offset = 0
    for i in range(target_i):
        while not state.startswith("...."):
            state = "." + state
            offset -= 1
        while not state.endswith("...."):
            state += "."

        if state in seen:
            prev_i, prev_score = seen[state]
            assert (i - prev_i) == 1
            current_score = score(state, offset)
            delta_score = current_score - prev_score
            final_score = current_score + (target_i - i) * delta_score
            print(final_score)
            return
        else:
            seen[state] = (i, score(state, offset))

        ns = ""
        for i in range(2, len(state) - 2):
            s = state[i - 2 : i + 3]
            ns += map[s]
        state = ns
        offset += 2
    print(score(state, offset))


def main():
    input_file = __file__.replace(".py", ".txt")
    with open(input_file) as f:
        data = f.read()
    solve(data, 20)
    solve(data, 50 * 10**9)


if __name__ == "__main__":
    main()