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

ok = 0
ng = 10**18

while ng - ok > 1:
  mid = (ok + ng) // 2
  cnt = max(mid - A, 0) + max(mid - B, 0) + max(mid - C, 0)
  if cnt > D:
    ng = mid
  elif cnt * Q + mid * P > R:
    ng = mid
  else:
    ok = mid

print(ok)