rt

#include<bits/stdc++.h>
#define M 10000001
#define inf 0x3f3f3f3f
#define ls p<<1
#define rs p<<1|1
#define ll long long
using namespace std;
inline ll read()
{
	ll k=0,f=0;char c=getchar();
	for(;!isdigit(c);c=getchar()) f|=c=='-';
	for(;isdigit(c);c=getchar()) k=(k<<1)+(k<<3)+(c^48);
	return f?-k:k;
}
ll n,phi[M],prime[M],cnt,ans;
bool isprime[M];
void KKK()
{
	for(ll i=2;i<=1e7;i++)
	{
		if(!isprime[i]) prime[++cnt]=i,phi[i]=i-1;
		for(ll j=1;j<=cnt&&prime[j]*i<=1e7;j++)
		{
			isprime[i*prime[j]]=1;
			if(i%prime[j]==0)
			{
				phi[i*prime[j]]=prime[j]*phi[i];
				break;
			}
			else phi[i*prime[j]]=(prime[j]-1)*phi[i];
		}
	}
}
int main()
{
	n=read(),phi[1]=1,KKK();
	for(ll i=1;i*i<=n;i++)
	{
		if(n%i==0)
		{
			ans=ans+i*phi[n/i];
			if(i*i!=n) ans=ans+(n/i)*phi[i];
		}
	}
	printf("%lld\n",ans);
	return 0;
}