R,P,Q = map(int,input().split())
A,B,C,D = map(int,input().split())

def is_ok(m):
    need_rate = m*P
    need_people = max(0,m-A) + max(0,m-B) + max(0,m-C)
    rem_people = max(0,A-m) + max(0,B-m) + max(0,C-m) + D
    if need_people > rem_people: return False
    need_rate += need_people*Q
    return R >= need_rate

ng = R+1
ok = 0
while ng-ok > 1:
    m = (ok+ng)//2
    if is_ok(m):
        ok = m
    else:
        ng = m
print(ok)