from typing import assert_type

def test(x: int | None, y: int | None) -> None:
    match x, y:
        case None, None:
            raise ValueError
        case int(m), None:
            u = m * 3
            v = m
        case None, int(n):
            u = n
            v = n // 3
        case _, _:
            raise ValueError

    assert_type(u, int)
    assert_type(v, int)