Nested Vlookups and If Statements

Hello,

I am looking to write a formula that does three things:

1. Vlookup that checks list A for an amount - returning amount if listed
2. Vlookup that checks list B for an amount - returning amount if listed

If my reference isn't in either list I want excel to complete an if statement to perform a calculation.

3. If Statement to complete a cacluation


Example attached.

Thanks for your help