/*by SilverN*/

 #include<iostream>

 #include<algorithm>

 #include<cstring>

 #include<cstdio>

 #include<cmath>

 using namespace std;

 const int mxn=;

 int read(){

     int x=,f=;char ch=getchar();

     while(ch<'' || ch>''){if(ch=='-')f=-;ch=getchar();}

     while(ch>='' && ch<=''){x=x*+ch-'';ch=getchar();}

     return x*f;

 }

 int pri[mxn],cnt=;

 long long phi[mxn],f[mxn];

 void PHI(){

     for(int i=;i<mxn;i++){

         if(!phi[i]){

             phi[i]=i-;

             pri[++cnt]=i;

         }

         for(int j=;j<=cnt && (long long)i*pri[j]<mxn;j++){

             if(i%pri[j]==){

                 phi[i*pri[j]]=phi[i]*pri[j];

                 break;

             }

             else phi[i*pri[j]]=phi[i]*(pri[j]-);

         }

     }

     return;

 }

 int main(){

     PHI();

     int i,j;

     for(i=;i<mxn;i++){//枚举因数

         for(j=i*;j<mxn;j+=i){

             f[j]+=i*phi[j/i];

         }

     }

     for(i=;i<mxn;i++)f[i]+=f[i-];

     while(){

         i=read();

         if(!i)break;

         printf("%lld\n",f[i]);

     }

     return ;

 }