The P and V operations on counting semaphores, where s is a counting semaphore, are defined as follows: P(s) : s = s - 1; ifs < 0 then wait; V(s) : s = s + 1; ifs <= 0 then wakeup a process waiting on s;

Assume that P_b and V_b the wait and signal operations on binary semaphores are provided. Two binary semaphores x_b and y_b are used to implement the semaphore operations P(s) and V(s) as follows: P(s) : Pb(Xb); s = s - 1; if (s < 0) { Vb(Xb) ; Pb(Yb) ; } else Vb(Xb);V(s) : Pb(Xb) ; s = s + 1; if (s <= 0) Vb(Yb) ; Vb(Xb) ;

The initial values of x_b and y_b are respectively