N,M,P,Q = map(int,input().split())
for _ in range(Q):
    x,f = map(int,input().split())
    if x % P == 0:
        print(M)
        continue
    ans = M // P
    t = (f * pow(x,-1,P)) % P
    if t > 0 and t <= M:
        ans += 1
    print(ans)