A, B, a, b = map(float,input().split()) cnt1 = 0 cnt2 = 0 while A > 0: A -= a if A >= 0: cnt1+=1 A -= (a-0.000001) while B > 0: B -= b if B >= 0: cnt2 +=1 B -= (b-0.000001) print(cnt1*cnt2)