Gratuity Calculation Excel Format UAE Rules

Can any send me a format in excel for gratuity calculation as per U.A.E with IF conditions. The Rule is as follows:
1st year 7 days salary of basic
2nd year 14 days basic salary
3rd year 21 days basic salary
3rd to 5 years 21 days basic salary x number of years upto 5
after 5 years 30 days basic salary x number of years served
All condition should come in one formula in one column
Can Anyone pls help

HI Chief,
Any luck? looking for the same and i hope someone can help me out with a Gratuity Calculator.
Regards,
Mark