computes the price of any desk a customer

A carpenter needs a program that computes the price of any desk a customer orders based on the following input fields: order number, desk length and width (three digits each, no decimals), type of wood (20 characters), and number of drawers (two digits). The price is computed as follows:
 

The price is computed as follows:
 

The charge for all desks is a minimum $200.
If the surface (length * width) is over 750 square inches, add $50.
If the wood is “mahogany” add $150; for “oak” add $125. No charge is added for “pine.”
For every drawer in the desk, there is an additional $30 charge.