Consider three concurrently executing threads in the same process using two semaphores s1 and s2. Assume s1 has been initialized to 1, while s2 has been initialized to 0. What are the possible values of the global variable x, initialized to 0, after all three threads have terminated?

/* thread A */

P(&s2);

P(&s1);

x = x*2;

V(&s1);

/* thread B */

P(&s1);

x = x*x;

V(&s1);

/* thread C */

P(&s1);

x = x+3;

V(&s2);

V(&s1);