A solar cell manufacturing company uses the pull method to supply lenses for an assembly line. Management's demand requires 500 lenses per day. Containers typically wait 0.5 days in a holding area. Each container holds 50 lenses. One container requires 2 days in fabrication time. Setup times are negligible. If the policy variable for unforeseen circumstances is 10 %, how many containers should management authorize for lens replenishment system?