N,M,P,Q = map(int,input().split())
for i in range(Q):
    x,f = map(int,input().split())
    y = f*pow(x,P-2,P)%P
    if y == 0:
        y = P
    if y >M:
        print(0)
    else:
        print((M-y)//P+1)