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 Pascal (FPC 2.6.2) (judge verdict: Wrong Answer)

var  s:array[1..1000]of  boolean;
     a,f:array[1..1000]of  int64;
     n,i,j,k,l:longint;
     tot,min:int64;
procedure  inf;
var  i,j,k,l:longint;
begin
  fillchar(f,sizeof(f),0);
  for  i:=1  to  n  do
    if  s[i]=false  then
      for  j:=i  to  n  do
        if  (j mod i=0)and(s[j]=false)then
          f[i]:=f[i]+a[j];
end;
begin
  readln(n);
  tot:=0;
  for  i:=1  to  n  do
    begin
      read(a[i]);
      inc(tot,a[i]);
    end;

  repeat
    inf;
    min:=999999999999999999;
    for  i:=1  to  n  do
      if  f[i]<min
        then
          begin
            min:=f[i];
            k:=i;
          end;
    if  min>=0  then  break;
    for  i:=1  to  n  do
      if  i mod k=0  then  s[i]:=true;
    dec(tot,min);
  until  false;
  writeln(tot);
end.