## implementation

#include <cstdio>
#include <functional>
#include <queue>
#include <unordered_map>
#include <vector>
#define repeat(i, n) for (int i = 0; (i) < int(n); ++(i))
using ll = long long;
using namespace std;

constexpr ll inf = ll(1e18)+9;

uint64_t pack(int i, int j) {
return (uint64_t(i) << 32) | j;
}
ll maximum_flow(int s, int t, int n, unordered_map<uint64_t, ll> & capacity /* adjacency matrix */) { // dinic, O(V^2E)
auto residue = [&](int i, int j) { auto key = pack(i, j); return capacity.count(key) ? capacity[key] : 0; };
vector<vector<int> > g(n); repeat (i,n) repeat (j,n) if (residue(i, j) or residue(j, i)) g[i].push_back(j); // adjacency list
ll result = 0;
while (true) {
vector<int> level(n, -1); level[s] = 0;
queue<int> q; q.push(s);
for (int d = n; not q.empty() and level[q.front()] < d; ) {
int i = q.front(); q.pop();
if (i == t) d = level[i];
for (int j : g[i]) if (level[j] == -1 and residue(i,j) > 0) {
level[j] = level[i] + 1;
q.push(j);
}
}
vector<bool> finished(n);
function<ll (int, ll)> augmenting_path = [&](int i, ll cur) -> ll {
if (i == t or cur == 0) return cur;
if (finished[i]) return 0;
finished[i] = true;
for (int j : g[i]) if (level[i] < level[j]) {
ll f = augmenting_path(j, min(cur, residue(i,j)));
if (f > 0) {
capacity[pack(i, j)] -= f;
capacity[pack(j, i)] += f;
finished[i] = false;
return f;
}
}
return 0;
};
bool cont = false;
while (true) {
ll f = augmenting_path(s, inf);
if (f == 0) break;
result += f;
cont = true;
}
if (not cont) break;
}
return result;
}

int main() {
// input
int n; scanf("%d", &n);
vector<int> a(n); repeat (i, n) scanf("%d", &a[i]);
// solve
const int src = n;
const int dst = n + 1;
unordered_map<uint64_t, ll> capacity;
ll sum_positive = 0;
repeat (i, n) {
if (a[i] > 0) {  // positive
sum_positive += a[i];
capacity[pack(src, i)] = a[i];
} else if (a[i] < 0) {  // negative
capacity[pack(i, dst)] = - a[i];
repeat (j, n) if (a[j] > 0) {  // positive
if ((j + 1) % (i + 1) == 0) {
capacity[pack(j, i)] = inf;
}
}
}
}
ll result = sum_positive - maximum_flow(src, dst, n + 2, capacity);
// output
printf("%lld\n", result);
return 0;
}