Consider a program with a global variable w initially set to zero, and two threads that run concurrently as scheduled on a single core by some arbitrary scheduler. The first thread does $$w $=$ w $+2$ five times, and the second thread does $$w $=$ w $-2$ ten times.

Considering any conceivable instruction interleaving, no matter how unlikely, fill in the blanks below.

a$)$ The smallest possible value of w once both threads terminate is: Blank $1.$ Fill in the blank, read surrounding text.

b$)$ The largest possible value of w once both threads terminate is: