#include <stdio.h>
# define IN "input.txt"
# define OUT "output.txt"
unsigned long long sum(int n){
unsigned long long otv=0;
for (int i=1; i*i<=n; i++)
if (!(n%i)){
otv+=i;
if(i*i!=n)otv+=n/i;}
return otv;}
int main(void){
unsigned long long n,otv=0;
freopen(IN,"r",stdin);
freopen(OUT,"w",stdout);
scanf("%I64d",&n);
otv=sum(n);
printf("%I64d",otv);
return 0;}
var
n,i,z:integer;
begin
readln(n);
for i:=1 to n do if n mod i=0 then inc(z,i);
writeln(z);
end.
