emptylast

function drop()
    while turtle.getItemCount(1) > 0 do
     turtle.dropUp()
     if turtle.getItemCount(1) > 0 then
       sleep(1)
     else
       return true
     end
   end
   return false
end

function main()
  drop()
  while true do
     local chest = peripheral.wrap("bottom")
     local dropped = false
     for i=23,26 do
       local itemInfo = chest.getStackInSlot(i)
       if itemInfo ~= nil and (itemInfo['qty'] * 1) > 0 then
         chest.pushIntoSlot('up', i, 64, 0)
         dropped = drop() or dropped
       end
     end
     if dropped then
       sleep(1)
     end
  end
end

main()