from collections import deque

N, H = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))


class D:
    def __init__(self):
        self.q = deque()
        self.a = 0
        self.b = 0
        self.s = 0

    def can_append(self, a, b) -> bool:
        s = self.s + b * (len(self.q) + 1)
        return s <= H

    def append(self, a, b):
        self.s += b * (len(self.q) + 1)
        self.q.append((a, b))
        self.a += a
        self.b += b

    def popleft(self):
        self.s -= self.b
        a, b = self.q.popleft()
        self.a -= a
        self.b -= b

    def score(self):
        assert self.s <= H
        return self.a


# a : 入力リスト
# pred : 条件
# op : 右端を伸ばす演算
# invop : 左端を縮める演算
def shakutori(a: list, pred, op, invop, identity):
    n = len(a)
    res = identity()
    hi = -1
    for lo in range(n):
        if lo > hi:
            hi = lo - 1
            res = identity()

        # 必要な分だけ伸ばす
        while hi+1 < n and pred(res, a[hi+1]):
            res = op(res, a[hi+1])
            hi += 1

        if lo <= hi:
            yield res, lo, hi

        # lo を一つ進める
        if lo <= hi:
            res = invop(res, a[lo])


# res に x を追加できるか
def pred(res: D, x):
    a, b = x
    return res.can_append(a, b)


# 伸ばす(res に x を追加)
def op(res: D, x):
    a, b = x
    res.append(a, b)
    return res


# 縮める(res から x を削除)
def invop(res: D, x):
    res.popleft()
    return res


ans = 0
for res, lo, hi in shakutori(list(zip(A, B)), pred, op, invop, D):
    ans = max(ans, res.score())

print(ans)