# Original solution
n = int(eval(input()))
h = [int(i) for i in input().split()]
a = [int(i) for i in input().split()]


class Bucket:
    def __init__(self, a, k, func=max, one=-10**18):
        self.n = len(a)
        self.k = k
        self.func = func
        self.one = one

        self.a = a[:]
        self.b = []
        for i in range(self.n // self.k):
            s = self.one
            for j in range(i * self.k, i * self.k + self.k):
                s = func(s, self.a[j])
            self.b.append(s)
        s = self.one
        for i in range(self.n // self.k * self.k, self.n):
            s = self.func(s, self.a[i])
        self.b.append(s)

    def get_0(self, index):
        s = self.one
        j = index // self.k

        for i in range(j):
            s = self.func(s, self.b[i])
        for i in range(j * self.k, index + 1):
            s = self.func(s, self.a[i])
        return s

    def get(self, index1, index2):
        s = self.one
        j1 = index1 // self.k
        j2 = index2 // self.k

        if j1 == j2:
            s = self.one
            for i in range(index1, index2 + 1):
                s = self.func(s, self.a[i])
            return s

        for i in range(index1, j1 * self.k + self.k):
            s = self.func(s, self.a[i])
        for i in range(j1+1, j2):
            s = self.func(s, self.b[i])
        for i in range(j2 * self.k, index2 + 1):
            s = self.func(s, self.a[i])
        return s

    def update(self, index, x):
        self.a[index] = self.func(x, self.a[index])
        self.b[index//self.k] = self.func(self.b[index//self.k], x)


buc = Bucket([0] * (n+1), max(10, int(n**0.5)))

for i in range(n):
    j = buc.get(0, h[i])
    buc.update(h[i], j + a[i])

print((buc.get(0, n)))


# Optimized solution
n = int(eval(input()))
h = [int(i) for i in input().split()]
a = [int(i) for i in input().split()]


class SegmentTree:
    def __init__(self, a, func=max, one=-10 ** 18):
        self.logn = (len(a) - 1).bit_length()
        self.n = 1 << self.logn
        self.func = func
        self.one = one

        self.b = [self.one] * (2 * self.n - 1)
        for i, j in enumerate(a):
            self.b[i + self.n - 1] = j
        for i in reversed(list(range(self.n - 1))):
            self.b[i] = self.func(self.b[i * 2 + 1], self.b[i * 2 + 2])

    def get_item(self, i):
        return self.b[i + self.n - 1]

    def update(self, i, x):
        self.b[i + self.n - 1] = x
        while i != 0:
            i = (i - 1) // 2
            self.b[i] = self.func(self.b[i * 2 + 1], self.b[i * 2 + 2])

    def update_func(self, index, x):
        i = index + self.n - 1
        self.b[i] = self.func(self.b[i], x)
        while i != 0:
            i = (i - 1) // 2
            self.b[i] = self.func(self.b[i * 2 + 1], self.b[i * 2 + 2])

    def get_segment(self, l, r, i=0):
        j = i - (1 << ((i + 1).bit_length() - 1))+1
        length = 1 << (self.logn - (i + 1).bit_length() + 1)
        ll = j * length
        rr = (j + 1) * length
        if l <= ll and rr <= r:
            return self.b[i]
        elif rr <= l or r <= ll:
            return self.one
        else:
            return self.func(self.get_segment(l, r, i * 2 + 1),
                             self.get_segment(l, r, i * 2 + 2))


seg = SegmentTree([0]*(n+1))

for i in range(n):
    j = seg.get_segment(0, h[i] + 1)
    seg.update_func(h[i], j + a[i])
print((seg.get_segment(0, n+1)))