#include<iostream>
using namespace std;
long X,ans;
long gcd(long a,long b){return b?gcd(b,a%b):a;}
bool f(long d)
{
	long L=d-1,R=X;
	if(L%2==0)L/=2;
	else R/=2;
	long g=gcd(L,d);
	d/=g;
	return R%d==0;
}
main()
{
	cin>>X;
	for(long i=1;i*i<=X;i++)
	{
		if(X%i==0)
		{
			if(f(i))ans+=i;
			if(i<X/i&&f(X/i))ans+=X/i;
		}
	}
	cout<<ans<<endl;
}