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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <cstdio>
#include <iostream>
#include <array>
#include <vector>
#include <deque>
#include <string>
#include <algorithm>
#include <functional>
#include <tuple>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <stack>
#include <utility>
#include <memory>
#include <valarray>
#include <climits>

using namespace std;

using ll = long long int;

#define REP(i, N) for (int i = 0; i < (N); ++i)
#define scanInt(x) int x; scanf("%d", &(x)); getchar();
#define scanLLInt(x) ll x; scanf("%lld", &(x)); getchar();
#define scanVecInt(A, N) vector<int> A(N); REP(i, N){scanf("%d", &(A[i])); getchar();}
#define scanVecLLInt(A, N) vector<ll> A(N); REP(i, N){scanf("%lld", &(A[i])); getchar();}

ll countScore(vector<ll>& A, int n)
{
    ll score = 0;
    for (int i = n; i <= A.size(); i += n){
        score += A[i - 1];
    }
    return score;
}

void breakScore(vector<ll>& A, int n)
{
    for (int i = n; i <= A.size(); i += n){
        A[i - 1] = 0;
    }
}

int main()
{
    scanInt(N);
    scanVecLLInt(A, N);
    for (int i = N; 1 <= i; --i){
        // for (auto& a : A) cout << a << " ";
        // cout << ": " << countScore(A, i) << endl;
        if (countScore(A, i) < 0) breakScore(A, i);
    }
    cout << countScore(A, 1) << endl;
}