poj2478

#include<iostream>
#include<cmath>
//#define LL long long
typedef long long LL;
using namespace std;

int phi[1000005];

int enlerFun(int n)
{
int  count = n;
for(int i=2;i<=n;i++)
if(n % i == 0)
{
count -= count / i;
while(n % i == 0)
n /= i;
}
return count;
}

void enlerPhi(){
memset(phi,0,sizeof(phi));
for (int i = 2 ; i <= 1000003 ; i ++ ){
if( !phi[i] ){
for(int j = i ; j <= 1000003 ; j += i){
if (!phi[j]){phi [j ] = j ;} //标记合数 等于一个数
phi [j] = phi [j] / i * ( i - 1 ) ;
}
}
}
}

void pt(){
for(int i=1;i<=100;i++){
printf("%d(%d) ",i,phi[i]);
}
}

LL work(LL x){
LL sum=0;
for(LL i=2;i<=x;i++){
sum=sum+phi[i];
}
return sum;
}

int main(){
enlerPhi();
//pt();
LL x;
while(scanf("%I64d",&x) && x!=0){
printf("%I64d\n",work(x));
}
return 0;
}