### BUGGY CODE ###

import sys
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
N = I()
h = LI()
a = LI()
dp = [0] * (N+1)
ans = int(0)

dp[h[0]] = a[0]
for i in range(N-1):
    dp[h[i+1]] = max(dp[:h[i+1]]) + a[i+1]

ans = max(dp)
print(ans)

### FIXED CODE ###

def examA():
    N = I()
    H = LI()
    dp = [inf]*(N)
    dp[0] = 0
    for i in range(N-1):
        dp[i+1] = min(dp[i+1],dp[i]+abs(H[i+1]-H[i]))
        if i<N-2:
            dp[i + 2] = min(dp[i + 2], dp[i]+abs(H[i + 2] - H[i]))
    ans = dp[-1]
    print(ans)
    return

def examB():
    N, K = LI()
    H = LI()
    dp = [inf]*N
    dp[0] = 0
    for i in range(N):
        for k in range(1,K+1):
            if i+k>=N:
                break
            if dp[i+k]>dp[i]+abs(H[i+k]-H[i]):
                dp[i+k] = dp[i]+abs(H[i+k]-H[i])
    ans = dp[-1]
    print(ans)
    return

def examC():
    N = I()
    A = [0]*N; B = [0]*N; C = [0]*N
    for i in range(N):
        A[i],B[i],C[i] = LI()
    dp = [[0]*3 for _ in range(N+1)]
    for i in range(N):
        dp[i+1][0] = max(dp[i][1],dp[i][2]) + A[i]
        dp[i + 1][1] = max(dp[i][0], dp[i][2]) + B[i]
        dp[i + 1][2] = max(dp[i][1], dp[i][0]) + C[i]
    ans = max(dp[N])
    print(ans)
    return

def examD():
    ans = 0
    print(ans)
    return

def examE():
    ans = 0
    print(ans)
    return

def examF():
    # LCS
    S = SI(); N = len(S)
    T = SI(); M = len(T)
    dp = [[0] * (M + 1) for _ in range(N + 1)]
    for i in range(N):
        for j in range(M):
            if S[i] == T[j]:
                dp[i + 1][j + 1] = max(dp[i + 1][j + 1], dp[i][j] + 1)
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j], dp[i][j+1])

    i = N; j = M
    ans = []
    while i > 0 and j > 0:
        if dp[i][j] == dp[i-1][j]:
            i -= 1
        elif dp[i][j] == dp[i][j-1]:
            j -= 1
        else:
            ans.append(S[i-1])
            i -= 1
            j -= 1
    print("".join(ans[::-1]))
    return

def examG():
    # http://zehnpaard.hatenablog.com/entry/2018/06/26/201512
    # トポロジカルソート
    def topological_sort(n,outs,ins):
        q = deque(v1 for v1 in range(n) if ins[v1] == 0)
        res = []
        while q:
            v1 = q.popleft()
            res.append(v1)
            for v2 in outs[v1]:
                ins[v2] -= 1
                if ins[v2] == 0:
                    q.append(v2)
        return res
    N, M = LI()
    V = [[]for _ in range(N)]
    start = [0]*N
    for _ in range(M):
        x,y = LI()
        x -= 1; y -= 1
        V[x].append(y)
        start[y] += 1
    Order = topological_sort(N, V, start)
#    print(Order)
    dp = [0]*N
    for i in Order:
        for v in V[i]:
            dp[v] = max(dp[v],dp[i]+1)
    ans = max(dp)
    print(ans)
    return

def examH():
    H, W = LI()
    A = [SI() for _ in range(H)]
    dp = [[0]*W for _ in range(H)]
    dp[0][0] = 1
    for i in range(H):
        for j in range(W):
            if A[i][j]=="#":
                continue
            dp[i][j] %=mod
            if i+1<H and dp[i+1][j]!="#":
                dp[i+1][j] +=dp[i][j]
            if j+1<W and dp[i][j+1]!="#":
                dp[i][j+1] +=dp[i][j]
    ans = dp[-1][-1]
    print(ans)
    return

def examI():
    N = I()
    P = LFI()
    dp = [[0]*(N+1) for _ in range(N+1)]
    dp[0][0] = 1
    for i in range(N):
        for j in range(i+1):
            dp[i+1][j+1] += dp[i][j]*P[i]
            dp[i+1][j] += dp[i][j]*(1-P[i])
    ans = 0
    for v in dp[N][(1+N//2):]:
        ans += v
    print(ans)
    return

def examJ():
    N = I()
    A = LI()
    dp = [[[0]*(N+1) for _ in range(N+1)]for _ in range(N+1)]
    S = Counter(A)
    print(S)
    dp[S[1]][S[2]][S[3]] = 0
    que = deque()
    que.append((S[1],S[2],S[3]))
    used = defaultdict(set)
    while(que):
        n1,n2,n3 = que.popleft()
        if used[(n1,n2,n3)]:
            continue
        used[(n1,n2,n3)] = True
        now = n1+n2+n3
        if n1>0:
            dp[n1-1][n2][n3] += dp[n1][n2][n3] + N/now * n1/now
            que.append((n1-1, n2, n3))
        if n2>0:
            dp[n1+1][n2-1][n3] += dp[n1][n2][n3] + N/now * n2/now
            que.append((n1+1,n2-1,n3))
        if n3>0:
            dp[n1][n2+1][n3-1] += dp[n1][n2][n3] + N/now * n3/now
            que.append((n1,n2+1,n3-1))
#    print(dp)
    ans = dp[0][0][0]
    print(ans)
    return

def examK():
    N, K = LI()
    A = LI()
    dp = [-1]*(K+1)
    for i in range(1,K+1):
        flag = False
        for a in A:
            if a>i:
                break
            if dp[i-a]==-1:
                flag = True
                break
        if flag:
            dp[i] = 1
#    print(dp)
    ans = dp[K]
    if ans==1:
        print("First")
    else:
        print("Second")
    return

def examM():
    N, K = LI()
    A = LI()
    dp = [[0]*(K+1) for _ in range(N+1)]
    dp[0][0] = 1
    for i in range(N):
        cum = [0]*(K+1)
        cum[0] = dp[i][0]
        for c in range(K):
            cum[c+1] = cum[c] + dp[i][c+1]
        for j in range(K+1):
            if j<=A[i]:
                dp[i+1][j] = cum[j]
            else:
                dp[i+1][j] = cum[j] - cum[j-A[i]-1]
            dp[i+1][j] %=mod
#    print(dp)
    ans = dp[N][K]%mod
    print(ans)
    return

def examN():
    N = I()
    A = LI()
    cumA = [0]*(N+1)
    for i in range(N):
        cumA[i+1] = cumA[i]+A[i]
    dp = [[inf]*(N) for _ in range(N)]
    for i in range(N):
        dp[0][i] = 0
    for i in range(N-1):
        for j in range(N-i-1):
            for k in range(i+1):
                cur = dp[i-k][j+k+1]+dp[k][j]+cumA[i+j+2]-cumA[j]
                dp[i+1][j] = min(dp[i+1][j],cur)
#    print(dp)
    ans = dp[N-1][0]
    print(ans)
    return

def examO():
    N = I()
    A = [LI() for _ in range(N)]
    loop = 2**N
    dp = [[0]*loop for _ in range(N+1)]
    dp[0][0] = 1
    for mask in range(loop):
        cur = 0
        for j in range(N):
            if mask&(1<<j)==(1<<j):
                cur +=1
        for i in range(N):
            if mask&(1<<i)==0 and A[i][cur]==1:
                dp[cur+1][mask|(1<<i)] += dp[cur][mask]
                dp[cur + 1][mask | (1 << i)] %=mod
#    print(dp)
    ans = dp[N][loop-1]
    print(ans)
    return

def examP():
    def dfs_dp(n,s,fords,visited):
        W = 1; B = 1
        visited[s] = True
        for v in fords[s]:
            if visited[v]:
                continue
            cur = dfs_dp(n, v, fords,visited)
            W *= sum(cur)
            B *= cur[0]
            W %= mod
            B %= mod
#        print(s,W,B)
        return (W,B)
    N = I()
    V = [[]for _ in range(N)]
    for _ in range(N-1):
        x,y = LI()
        x -=1; y -=1
        V[x].append(y)
        V[y].append(x)
    visited = [False]*N
    ans = dfs_dp(N,0,V,visited)
    print(sum(ans)%mod)
    return

def examQ():
    # 一点更新、区間取得
    class segment_():
        def __init__(self, A, n, segfunc):
            #####単位元######要設定0or1orinf
            self.ide_ele = 0
            ####################
            self.num = 1 << (n - 1).bit_length()
            self.seg = [self.ide_ele] * 2 * self.num
            self.segfunc = segfunc
            # set_val
            for i in range(n):
                self.seg[i + self.num] = A[i]
                # built
            for i in range(self.num - 1, 0, -1):
                self.seg[i] = self.segfunc(self.seg[2 * i], self.seg[2 * i + 1])

        def update(self, k, r):
            k += self.num
            self.seg[k] = r
            while k:
                k >>= 1
                self.seg[k] = self.segfunc(self.seg[k * 2], self.seg[k * 2 + 1])

        # 値xに1加算
        def update1(self, k):
            k += self.num
            self.seg[k] += 1
            while k:
                k >>= 1
                self.seg[k] = self.segfunc(self.seg[k * 2], self.seg[k * 2 + 1])

        def updateneg1(self, k):
            k += self.num
            self.seg[k] -= 1
            while k:
                k >>= 1
                self.seg[k] = self.segfunc(self.seg[k * 2], self.seg[k * 2 + 1])

        def query(self, p, q):
            if q < p:
                return self.ide_ele
            p += self.num;
            q += self.num
            res = self.ide_ele
            while p < q:
                if p & 1 == 1:
                    res = self.segfunc(res, self.seg[p])
                    p += 1
                if q & 1 == 1:
                    q -= 1
                    res = self.segfunc(res, self.seg[q])
                p >>= 1;
                q >>= 1
            return res
    N = I()
    H = LI()
    maxH = max(H)
    A = LI()
    Seg_max = segment_([0]*(maxH+1), (N+1), lambda a, b: max(a,b))
    dp = [0]*(maxH+1)
    cur = 0
    for i in range(N):
        h = H[i]
        cur = Seg_max.query(0,h+1)
        dp[i] = cur + A[i]
        Seg_max.update(h,dp[i])
    ans = max(dp)
    print(ans)
    return

def examR():
    def list_dot(A1,A2):
        res = [[0]*len(A2) for _ in range(len(A1))]
        for i in range(len(A1)):
            for j in range(len(A2)):
                cur = 0
                for k in range(len(A1[0])):
                    cur += A1[i][k]*A2[k][j]
                res[i][j] = cur%mod
        return res
    N, K = LI()
    A = [LI() for _ in range(N)]
    now = [[1]*N]
    while(K>0):
        if K%2==1:
            now = list_dot(now,A)
        K //=2
        A = list_dot(A,A)
    ans = 0
    for i in now:
        for k in i:
            ans += k
            ans %= mod
    print(ans)
    return

def examS():
    class ModInt:
        def __init__(self, x):
            self.x = x % MOD

        def __str__(self):
            return str(self.x)

        __repr__ = __str__

        def __add__(self, other):
            return (
                ModInt(self.x + other.x) if isinstance(other, ModInt) else
                ModInt(self.x + other)
            )

        def __sub__(self, other):
            return (
                ModInt(self.x - other.x) if isinstance(other, ModInt) else
                ModInt(self.x - other)
            )

        def __mul__(self, other):
            return (
                ModInt(self.x * other.x) if isinstance(other, ModInt) else
                ModInt(self.x * other)
            )

        def __truediv__(self, other):
            return (
                ModInt(
                    self.x * pow(other.x, MOD - 2, MOD)
                ) if isinstance(other, ModInt) else
                ModInt(self.x * pow(other, MOD - 2, MOD))
            )

        def __pow__(self, other):
            return (
                ModInt(pow(self.x, other.x, MOD)) if isinstance(other, ModInt) else
                ModInt(pow(self.x, other, MOD))
            )

        __radd__ = __add__

        def __rsub__(self, other):
            return (
                ModInt(other.x - self.x) if isinstance(other, ModInt) else
                ModInt(other - self.x)
            )

        __rmul__ = __mul__

        def __rtruediv__(self, other):
            return (
                ModInt(
                    other.x * pow(self.x, MOD - 2, MOD)
                ) if isinstance(other, ModInt) else
                ModInt(other * pow(self.x, MOD - 2, MOD))
            )
        def __rpow__(self, other):
            return (
                ModInt(pow(other.x, self.x, MOD)) if isinstance(other, ModInt) else
                ModInt(pow(other, self.x, MOD))
            )
    def ketadp(a,D):
        n = len(a)
        dp = [[[ModInt(0)]*D for _ in range(2)] for _ in range(n+1)]
        dp[0][0][0] = 1
        for i, less, hasD in itertools.product(range(n), (0, 1), range(D)):
            max_d = 9 if less else int(a[i])
            for d in range(max_d + 1):
                less_ = less or d < max_d
                hasD_ = (hasD + d)%D
                dp[i + 1][less_][hasD_] += dp[i][less][hasD]

        ans = sum(dp[n][less][0] for less in (0, 1))
        return ans
    K = SI()
    D = I()
    ans = ketadp(K,D)
    ans = ans-1
    print(ans)
    return

def examT():
    return

def examU():
    N = I()
    A = [LI() for _ in range(N)]
    mask = 2**N
    cst = [0]*mask
    for i in range(mask):
        cur = 0
        for j in range(N):
            for k in range(j+1,N):
                if i&(1<<j)==(1<<j) and i&(1<<k)==(1<<k):
                    cur += A[j][k]
        cst[i] = cur
    dp = [0]*mask
    for m in range(mask):
        maskT = m
        while(maskT > 0):
            cur = dp[m-maskT] + cst[maskT]
            dp[m] = max(dp[m], cur)
#            print(m,maskT,cur)
            # 次の部分maskT
            maskT = (maskT - 1) & m
#    print(dp)
    ans = dp[-1]
    print(ans)
    return

def examX():
    N = I()
    W = [[] for _ in range(N)]
    for i in range(N):
        W[i] = LI()
    W.sort(key=lambda x:x[1])
    maxS = W[-1][1]
    print(W)
    dp = [[0]*(maxS+2) for _ in range(N+1)]
    for i in range(N):
        ns = W[i][1]
        nw = W[i][0]
        nv = W[i][2]
        for j in range(maxS+2):
            dp[i+1][j] = max(dp[i+1][j],dp[i][j])
        for j in range(ns+1):
            dp[i+1][min(j+nw,maxS+1)] = max(dp[i+1][j],dp[i][j]+nv)
    ans = max(dp[N])
    print(dp)
    print(ans)
    return

import sys,copy,bisect,itertools,heapq,math
from heapq import heappop,heappush,heapify
from collections import Counter,defaultdict,deque
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
def LFI(): return list(map(float,sys.stdin.readline().split()))
def LSI(): return list(map(str,sys.stdin.readline().split()))
def LS(): return sys.stdin.readline().split()
def SI(): return sys.stdin.readline().strip()
global mod,mod2,inf,alphabet,MOD
mod = 10**9 + 7
mod2 = 998244353
MOD = mod
inf = 10**18
alphabet = [chr(ord('a') + i) for i in range(26)]

sys.setrecursionlimit(10**6)

if __name__ == '__main__':
    examQ()

"""

"""