Software-Engineering

Assume that the delivered lines of code L of a software is related to the effort E in person months and duration t in calendar months by the relation L = P* (E/B)^1/3 * t^4/3, where P and B are two constants for the software process and skills factor. For a software project, the effort was estimated to be 20 person months and the duration was estimated to be 8 months. However, the customer asked the project team to complete the software project in 4 months. What would be the required effort in person months?