A1 python

import math

c, x, y, z, m, s, f, e, t = map(int, input().split())
# x = int(input())
# y = int(input())
# print(x//y)


# набор монет
coins = 0
i_coins = 0  # кол во ходов
storages = 0  # кол во хранилищ
storages_need = math.ceil((c-x)/z)

# покупаем хранилища
while storages < storages_need:
    i_coins += 1
    coins += s
    storages_buy = min(storages_need-storages, coins//y)
    coins -= storages_buy*y
    storages += storages_buy
    coins = min(storages*z + x, coins)
i_coins += math.ceil((c-coins)/s)

# смэрть
coins = 0
i_war = 0  # кол во ходов
wars = 0

while e >= 0:
    i_war += 1
    coins += s
    wars_buy = coins//f
    coins -= wars_buy*f
    e -= wars_buy

print(min(i_coins*m, i_war*m + t))