Problem:
Score : 700 points

Problem Statement

We have N gemstones labeled 1 through N.

You can perform the following operation any number of times (possibly zero).

Select a positive integer x, and smash all the gems labeled with multiples of x.

Then, for each i, if the gem labeled i remains without getting smashed, you will receive a_i yen (the currency of Japan).
However, a_i may be negative, in which case you will be charged money.

By optimally performing the operation, how much yen can you earn?

Constraints

All input values are integers.

1 \leq N \leq 100

|a_i| \leq 10^9

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

Print the maximum amount of money that can be earned.

Sample Input 1

6
1 2 -6 4 5 3

Sample Output 1

12

It is optimal to smash Gem 3 and 6.

Sample Input 2

6
100 -100 -100 -100 100 -100

Sample Output 2

200

Sample Input 3

5
-1 -2 -3 -4 -5

Sample Output 3

0

It is optimal to smash all the gems.

Sample Input 4

2
-1000 100000

Sample Output 4

99000

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

import sys
import math
from operator import add
import functools

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

#for i in range(math.floor(len(A)/2),len(A)):
#	if A[i]<0:
#		A[i]=0
#sum=[0]
j=N-1
while j>=0:
	#print(j)
	#print(A[j::j+1])
	if functools.reduce(add,A[j::j+1])<0:
		i=j
		while i<N:
			A[i]=0
			i+=j+1
	j-=1
	#print(A)
print(functools.reduce(add,A))