I assume you can write the for-loop to examine each element in the list? If you have a question about how to find whether an element is a numeral, or some other question about this, don't hesitate to post it.
It sounds as if you might have a design problem with a List of alternating Strings and ints. It suggests maybe you need a Map instead, or an object which encapsulates the two values.
Don't get me started about those stupid light bulbs.