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


ok=0
ng=10**18
while ng-ok>1:
    X=(ok+ng)//2
    pls=max(0,X-A)+max(0,X-B)+max(0,X-C)
    if pls>D:
        ng=X
        continue
    need=Q*pls+X*P
    if need<=R:
        ok=X
    else:
        ng=X

print(ok)