H,W,LA,LB,KA,KB = map(int,input().split())
HW = H * W
ans = 10 ** 7
tmp = 10 ** 7
for i in range(10**6):
    lb = -1
    hb = 10 ** 6
    while hb - lb > 1:
        mid = (lb + hb) // 2
        tmp = min(H,LA*i) * min(W,LB*mid) + KA * i + KB * mid
        if tmp >= HW:
            hb = mid
        else:
            lb = mid
        #print(i,hb,tmp)
    if hb == 10 ** 6:
        continue
    if ans > i + hb:
        ans = i + hb
        #print(i,hb)
    else:
        break

print(ans)