A JIT$/$lean system uses kanban cards to authorize production and movement of materials. In one portion of the system, a work centre uses an average of $120$ pieces of a part per hour. The manager has assigned a safety factor of $1\mathrm{.}00.$ Standard containers are designed to hold six dozen pieces each. The cycle time for a kanban is $144$ minutes.

How many kanbans are needed? $($Round the final answer to the nearest whole number.$)$

Number of Kanbans