how to Export Merge PDF file using C#

Question

hello friends,
I have problem with Crystal report actually i want to marge to PDF file using C#... i have two reports one is total of employees and second is Break Up of Employees salary which call annexure.. so i want to export both file in one time.. so tell me if its possible to Marge Tow PDF file into C#... if yes then please give me Code or any kind of Example..........

thanks in Advance