H,W,LA,LB,KA,KB = map(int,input().split())

ans = 10 ** 8


def calc(w,h):
    a = w * KB + h * KA
    gyo = min(w * LB,W)
    retu = min(h * LA,H)
    return a + gyo * retu >= H * W
for w in range(W + 1):
    if not calc(w,H + W - w):
        continue
    end = H + W - w
    start = -1
    while end -start > 1:
        mid = end +start >> 1
        if calc(w,mid):
            end = mid
        else:
            start = mid
    if w + end < ans:
        ans = w + end
print(ans)