def bidirectional_dict(d: dict) -> dict:
    for k, v in list(d.items()):
        d[v] = k
    return d


class NoSuchStudentException(Exception):
    """Raised when plants are requested for a student not assigned a plot."""

class Garden:
    PLANTS = bidirectional_dict({
        "Tráva":	"G",
        "Ďatelina":	"C",
        "Reďkovky":	"R",
        "Fialky":	"V"
    })

    students = {}

    rows: list[str]


    def __init__(self, seq: str, students: list[str] = ["Alena", "Boris", "Cyril", "Daniel", "Eva", "František", "Gitka", "Helena", "Ivana", "Jozef", "Karol", "Ladislav"]):
        self.rows = seq.split("\n")
        if students is not None:
            self.students = {name: "" for name in sorted(students)}
        self.parse()

    def parse(self):
        for row in self.rows:
            for x in range(0, len(row), 2):
                self.students[list(self.students.keys())[x//2]] += row[x:x+2]

    def plants(self, name: str) -> list:
        student_plants = self.students.get(name)
        if student_plants is None:
            raise NoSuchStudentException(f"Student {name} is not assigned a plot.")
        return [self.PLANTS.get(c) for c in student_plants]