How many?

Feet

The foot is a unit of length in the British imperial and United States customary systems of measurement. Since the International Yard and Pound Agreement of 1959, one foot is defined as 0.3048 meters exactly. In both customary and imperial units, one foot comprises 12 inches and one yard comprises three feet. The foot is taken from the average length of a mans foot, but in older times was just uner 12 inches.

Yards

The yard is an English unit of length, in both the British imperial and US customary systems of measurement, that comprises 3 feet or 36 inches. Did you know that a yard of ale, whilst being 2.5 imperial pints of beer, is so called because the glass is a yard long.