employees hiliday planner 2018

HI EVEYONE,
I would like to make chart for employees for their planed vacation of 2018 .every employee has 2 vacations a year ,1-3 WEEKS PER VACATION
Can you help to edit or any suggestion to see how many employees took vacation in the same week of the year in the chart?
If anyone have different templates than this plz. Help me.

Thank you

if layout is like in the file
=MAX(MMULT((B2:B9>=TRANSPOSE(B2:B9))*(C2:C9<=TRANSPOSE(C2:C9)),ROW(B2:B9)^0)) as array formula