#include<iostream>
using namespace std;
int main()
{
unsigned a,c=0,k;
while(cin>>a)
{
k=a;
for(int b=2;b<=a;b++)
{
if(a%b==0)
{
c = c+b;
a = a/b;
b=1;
}
}
if(k==1)
{
c=1;
}
cout<<c<<endl;
c = 0 ;
}
}

要用質數篩法