n, m, p, q = map(int, input().split())

inv = [0]*(n+1)
for i in range(1, n+1):
    inv[i] = pow(i, p-2, p)

for _ in range(q):
    x, f = map(int, input().split())
    y_cand = f*inv[x]%p
    if y_cand == 0:
        y_cnt = m//p
    else:
        y_cnt = m//p + int(m%p >= y_cand)
    print(y_cnt)