Should I do all the exercises in K&R?

This is a quick slightly subjective question I need to ask. In order to become a proficient C programmer, I felt I'd learn C from the k&r. I find the book a little easygoing, difficult to understand sometimes but easygoing on the whole.

My question here is, do I have to absoultely do all the exercises (even those that stumped me) to become a proficient programmer in C? Or can I skip most of them? The format and layout of the questions asked are ... difficult, at best without using the tools available to C's rich set of libraries.