h,w,la,lb,ka,kb = map(int,input().split())
ans = h+w
for i in range(h+1):
    ng = -1; ok = w+1
    while ok-ng>1:
        j = (ng+ok)//2
        if min(i*la,h)*min(j*lb,w)+i*ka+j*kb>=h*w: ok = j
        else: ng = j
    if ok<=w: ans = min(ans,i+ok)
print(ans)