program crazy_teacher;
var
        ch,sum,i : integer;
begin
readln(ch);
        ch:=abs(ch);
        sum:= 0;
        for i:=2 to ch do
        begin
                if (ch mod i)=0 then begin
                   inc(sum, i);
                   while (ch mod i)=0 do ch:=ch div i
                end;
        end;
        writeln(sum);
end;

#include <iostream>
using namespace std;

int SumSimNum(int InNumber)
{
    int * SimNum = new int[100];
    if (SimNum == NULL)
        return 0;
    int result = 0;
    int CountNum = 0;
    for(int i = 2; i <= (InNumber/2); i++)
      if ((InNumber%i) == 0)
      {
          bool b = true;
          for(int a = 0; a < CountNum; a++)
            if ((i%SimNum[a]) == 0)
            {
                b = false;
                break;
            }
          if (b)
          {
              result+=i;
              SimNum[CountNum] = i;
              CountNum++;
          }
    }
    delete[] SimNum;
    return result;
}

int main()
{
    while(true)
    {
        int Number = 0;
        cin >> Number;
        cout << SumSimNum(Number) << endl;
    }
}