>>> from contrasenyes import primera_valida

>>> primera_valida(["clau12", "ClauA2", "ABCD12B"], [2, 3, 1], 8)
('ABCD12B', 1)
>>> primera_valida(["clau12", "admin12"], [5, 1], 11)
('', -1)
>>> primera_valida(["admin12", "Porta34"], [2, 1], 8)
('Porta34', 1)

>>> primera_valida(["clau1234", "admin123", "ABCD123"], [5, 1, 1], 13)
('ABCD123', 1)
>>> primera_valida(["ABCadmin999", "Clau123"], [3, 2], 14)
('Clau123', 2)
>>> primera_valida(["clau123", "Clau123"], [1, 2], 14)
('Clau123', 2)