#include <bits/stdc++.h>
#define CHOR 1000001
#define pb push_back
using namespace::std;

typedef long long ll;

int lo[CHOR], mu[CHOR], phi[CHOR];
ll f[CHOR];
int zex[10000];
ll ans[CHOR];
bool vis[CHOR];

void phi_calc(void)
{
	for(int i=1;i<CHOR;i++)
	{
		lo[i] = i;
		mu[i] = 1;
	}
	for(int i=2;i*i<CHOR;i++)
	{
		if(lo[i] == i)
		{
			for(int j=i*i;j<CHOR;j+=i)
			{
				if(lo[j] == j) lo[j] = i;
			}
		}
	}
	//std::cout<<lo[18]<<"\n";
	for(int i=2;i<CHOR;i++)
	{
		int j = i;
		while(lo[j/lo[j]] != lo[j]){
			j /= lo[j];
		}
		//std::cout<<i<<" "<<j<<"\n";
		if(j != 1)
		mu[i] = 0;
		else mu[i] = -mu[i/lo[i]];
		//std::cout<<mu[i]<<"\n";
	}
	for(int i=1;i<CHOR;i++)
	{
		for(int j=i;j<CHOR;j+=i)
		phi[j] += (j/i)*mu[i];
	}
	for(int i=1;i<CHOR;i++)
	f[i] = f[i-1] + phi[i];
	return;
}

int main(void)
{
	phi_calc();
	int n;
	scanf("%d",&n);
	int len;
	while(n)
	{
		ll G = 0;
		if(vis[n]){
			printf("%lld\n",ans[n]);
			scanf("%d",&n);
			continue;
		}
		/*
		len = 0;
		for(int i=1,lx=0;i<=n;i=lx+1)
		{
			zex[len++]= i;
			lx = n/(n/i);
		}
		for(int i=0;i<len;i++)
		{
			if(i != len-1)
			G += (1LL*(n/zex[i])*(n/zex[i] - 1)/2)*(f[zex[i+1]-1] - f[zex[i]-1]);
			else G +=(1LL*(n/zex[i])*(n/zex[i] - 1)/2)*(f[n] - f[zex[i]-1]);
		}
		*/
		int last = 1;
		int lx = n/(n/1);
		for(int i=lx+1;i<=n;i=lx+1)
		{
			G += (1LL*(n/last)*(n/last - 1)/2)*(f[i-1] - f[last-1]);
			lx = n/(n/i);
			last = i;
		}
		G += (1LL*(n/last)*(n/last - 1)/2)*(f[n] - f[last-1]);

		vis[n] = true;
		ans[n] = G;
		printf("%lld\n",G);
		scanf("%d",&n);
	}
	return 0;
}