Dear Sir,
I am an expert Mathematician and Programmer. You can verify my skill level by checking my previous projects.
I can provide a program whih includes appropriate algorith to the required alculation. In fact I will provide a program, in which you can specify variable such as, inflation rate, return percentage, annual withdrawal amount, remaining balanace after specified years, and then my software will calculate input amount at the begining. I will provide quality,easy to use software for this as well as, well strutured, well commented source code for you.
Thanks,
-R