 Complete the following phrase:  The number of cars entered by one team into a single race was not strictly limited in the 1950s and early 1960s. Since the season teams were generally allowed to enter only two regular cars, with the third car reserved for an occasional driver. Entering more than three cars was exceptionally tolerated, most notably regarding the BRM team in the and seasons. However, many teams during this period entered only two cars, e.g. Ferrari have entered no more than two cars with one exception at the 