def General_Binary_Increase_Search_Integer(L, R, cond, default=None):
    """ 条件式が単調増加であるとき, 整数上で二部探索を行う.

    L: 解の下限
    R: 解の上限
    cond: 条件(1変数関数, 広義単調増加を満たす)
    default: Lで条件を満たさないときの返り値
    """

    if not(cond(R)):
        return default

    if cond(L):
        return L

    R+=1
    while R-L>1:
        C=L+(R-L)//2
        if cond(C):
            R=C
        else:
            L=C
    return R

#==================================================
def solve():
    H,W,LA,LB,KA,KB=map(int,input().split())

    inf=float("inf")
    X=inf
    for A in range(H+1):
        def check(b):
            s=min(H,A*LA)
            t=min(W,b*LB)
            return s*t+A*KA+b*KB>=H*W

        B=General_Binary_Increase_Search_Integer(0,H*W+1,check,inf)
        X=min(X,A+B)
    return X
#==================================================
print(solve())