VMSS O(n^2) P7 PrePreWindsor on DMOJ

import math
N=int(input())
iv=[]
cardv=[]
def m(i):
    maxwithprev=0
    for i in range(0,len(cardv)):
        if cardv[i]+cardv[-i-1]>maxwithprev:
            maxwithprev=cardv[i]+cardv[-i-1]
    return maxwithprev
for i in range(N):
    iv.append(int(input()))
for i in range(N):
    if len(cardv)==0:
        cardv.append(iv[i])
    elif len(cardv)==1:
        cardv.append(max(iv[i],2*iv[i-1]))
    else:
        prevmax=m(i)
        cardv.append(max(iv[i],prevmax))
print(cardv[-1])