ll go(ll n)
{
	return n*(n+1)/2;
}

ll G(int n)
{
	ll ans=0;
	for(ll l=1,r;l<=n;l=r+1){
		r=n/(n/l);
		ans+=(go(r)-go(l-1))*(n/l);
	}
	return ans;
}

int main()
{
	while(~sd(n)){
		pll(G(G(n)));
	}
}