#include "bits/stdc++.h"
#include <sys/timeb.h>
#include <fstream>
#include <random>

using namespace std;

#define repr(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repr(i,0,n)
#define reprrev(i,a,b) for(int i=(int)(b)-1;i>=(int)(a);i--)
#define reprev(i,n) reprrev(i,0,n)
#define repi(itr,ds) for(auto itr=ds.begin();itr!=ds.end();itr++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define mp make_pair
#define mt make_tuple
#define INF 1050000000
#define INFR INT_MAX
#define INFL (long long)(4e18)
#define INFLR LLONG_MAX
#define EPS (1e-10)
#define MOD 1000000007
#define PI 3.1415926536
#define RMAX 4294967295

typedef long long ll;
typedef pair<int, int> Pi;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<bool> vb;
typedef vector<char> vc;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<Pi> vPi;
typedef vector<vector<int> > vvi;
typedef vector<vector<bool> > vvb;
typedef vector<vector<ll> > vvll;
typedef vector<vector<char> > vvc;
typedef vector<vector<string> > vvs;
typedef vector<vector<double> > vvd;
typedef vector<vector<Pi> > vvPi;
typedef priority_queue<int, vector<int>, greater<int> > pqli;
typedef priority_queue<ll, vector<ll>, greater<ll> > pqlll;
typedef priority_queue<Pi, vector<Pi>, greater<Pi> > pqlP;
struct Edge {
	ll from, to, cost;
	bool operator<(Edge e) {
		return cost < e.cost;
	}
};
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;
template <class T>
using vec = vector<T>;
template<class T>
using pql = priority_queue<T, vector<T>, greater<T>>;
string debug_show(Pi a) {
	return "(" + to_string(a.first) + "," + to_string(a.second) + ")";
}
string YN(bool y) { return (y ? "YES" : "NO"); }
string yn(bool y) { return (y ? "Yes" : "No"); }
string ON(bool y) { return (y ? "OK" : "NG"); }

template<class T>
struct augEdge {
	T from, to;
	int cost;
	bool operator<(augEdge e) { return cost < e.cost; }
	bool operator>(augEdge e) { return cost > e.cost; }
};
template<class T>
using augGraph = vector<augEdge<T>>;

int dir4[4][2] = { {0,-1},{-1,0},{1,0},{0,1} };
int dir8[8][2] = { {-1,-1},{0,-1},{1,-1},{-1,0},{1,0},{-1,1},{0,1},{1,1} };

// [a,b]の乱数
int irand(int a, int b) {
	static mt19937 Rand(static_cast<unsigned int>(time(nullptr)));
	uniform_int_distribution<int> dist(a, b);
	return dist(Rand);
}

// [a,b)の乱数
double drand(int a, int b) {
	static mt19937 Rand(static_cast<unsigned int>(time(nullptr)));
	uniform_real_distribution<double> dist(a, b);
	return dist(Rand);
}

//=======ここまでテンプレート===============================================

struct edge { int to; ll cap; int rev; };
#define MAX_V 102
vector<edge> G[MAX_V];	// グラフの隣接リスト表現
ll level[MAX_V];	// sからの距離
int iter[MAX_V];	// どこまで調べ終わったか

					// fromからtoへ向かう容量capの辺をグラフに追加する
void add_edge(int from, int to, ll cap)
{
	G[from].push_back(edge{ to, cap, (int)G[to].size() });
	G[to].push_back(edge{ from, 0, (int)G[from].size() - 1 });
}

// sからの最短距離をBFSで計算
void bfs(int s) {
	memset(level, -1, sizeof(level));
	queue<int> que;
	level[s] = 0;
	que.push(s);
	while (!que.empty()) {
		int v = que.front();
		que.pop();
		for (int i = 0; i < G[v].size(); i++) {
			edge &e = G[v][i];
			if (e.cap > 0 && level[e.to] < 0) {
				level[e.to] = level[v] + 1;
				que.push(e.to);
			}
		}
	}
}

// 増加パスをDFSで探す
ll dfs(int v, int t, ll f) {
	if (v == t)return f;
	for (int &i = iter[v]; i < G[v].size(); i++) {
		edge &e = G[v][i];
		if (e.cap > 0 && level[v] < level[e.to]) {
			ll d = dfs(e.to, t, min(f, e.cap));
			if (d > 0) {
				e.cap -= d;
				G[e.to][e.rev].cap += d;
				return d;
			}
		}
	}
	return 0;
}

// sからtへの最大流を求める
ll max_flow(int s, int t) {
	ll flow = 0;
	while (true) {
		bfs(s);
		if (level[t] < 0)return flow;
		memset(iter, 0, sizeof(iter));
		ll f;
		while ((f = dfs(s, t, INF)) > 0) {
			flow += f;
		}
	}
}
int N;
vi a;

int main(void) {
	cin >> N;
	a = vi(N + 1, 0);
	ll sum = 0;
	rep(i, N) {
		cin >> a[i + 1];
		if (a[i + 1] >= 0) {
			add_edge(i + 1, N + 1, a[i + 1]);
			sum += a[i + 1];
		}
		else {
			add_edge(0, i + 1, -a[i + 1]);
		}
	}
	repr(i, 1, N + 1) {
		repr(j, 2, N / i + 1) {
			add_edge(i, i*j, INFR);
		}
	}

	cout << sum - max_flow(0, N + 1) << endl;

	return 0;
}

Measured memory_bytes: 256