#include<stdio.h>

typedef long long Int;

Int n,t,ans,prime[20000];

bool flag[1000000];

Int ou(Int k)
{
	Int i,s=k,tmp=k;
	for(i=1;i<=t&&prime[i]*prime[i]<=k;i++)
	{
		if(k%prime[i]==0)s=s/prime[i]*(prime[i]-1);
		while(k%prime[i]==0)k/=prime[i];
	}
	if(k>1)s=s/k*(k-1);
	return s;
}

int main()
{
	freopen("gcdsum.in","r",stdin);
	freopen("gcdsum.out","w",stdout);
	Int i,j;
	scanf("%lld",&n);
	for(i=2;i*i<=n;i++)
	{
		if(!flag[i])
		{
			prime[++t]=i;
			for(j=i+i;j*j<=n;j+=i)
			{
				flag[j]=true;
			}
		}
	}
	for(i=1;i*i<=n;i++)
	{
		if(n%i==0)
		{
			if(i*i==n)
			{
				ans+=ou(i)*i;
				break;
			}
			ans+=ou(i)*n/i;
			ans+=ou(n/i)*i;
		}
	}
	printf("%lld\n",ans);
	return 0;
}