Uva 10820 - Send a Table

// Header file begin
#include<iostream>
#include<cstdio>
#include<cstring>
#include<map>
#include<string>
#include<vector>
#include<cmath>
#include<cctype>
#include<sstream>
#include<set>
#include<list>
#include<stack>
#include<utility>
#include<queue>
#include<algorithm>
#include<cstdlib>
#include<bitset>
#include<iomanip>
// End
//..........
// Macro
#define sf scanf
#define pf printf
#define lp1(i,n) for(i=0;i<n;i++)
#define lp2(i,n) for(i=1;i<=n;i++)
#define mset(c,v) memset(c,v,sizeof(c))
#define cp(a) cout<<" "<<a<<" "
#define nl puts("")
#define sq(x) ((x)*(x))
#define all(x) x.begin(),x.end()
#define reall(x) x.rbegin(),x.rend()
#define s_wap(x,y) x^=y;y^=x;x^=y;
#define sz size()
#define gc getchar()
#define pb push_back
#define freader freopen("input.txt","r",stdin)
// End.........

// Size
#define mx7 20000100
#define mx6 1500000
#define mx5 100005
#define mx4 1000100
#define inf 1<<30                                           //infinity value
#define eps 1e-9
#define mx (65540)
#define mod 1000000007
#define pi acos(-1.0)

// Macros for Graph

#define white 1
#define gray 2
#define black 3
#define nil 0

using namespace std;
/***************/

// typedef

typedef long long LL;
typedef long L;
typedef unsigned long long ull;
typedef unsigned long ul;
typedef unsigned int ui;
typedef pair<int, int> pii;
typedef vector<int>vi;
typedef vector<long long> vll;
typedef vector<long>vl;
typedef vector<char>vch;
typedef vector<string>vs;
typedef map<int,int>mpii;
typedef map<int,bool>mpbi;
typedef map<long,bool>mpbl;
typedef map<long long,bool>mpbll;
typedef map<char,int>mpci;
typedef map<char,bool>mpbc;
typedef map<string,int>mpsi;
typedef map<long long,long long>mpll;

// template

template<class T> T gcd(T a, T b ) {return b!=0?gcd<T>(b,a%b):a;}
template<class T> T large(T a, T b ) {return a>b?a:b;}
template<class T> T small(T a, T b ) {return a<b?a:b;}
template<class T> T diffrnce(T a, T b) {return a-b<0?b-a:a-b;}

#define TSz 50019

LL phi[TSz+9];

void Euler_phi()
{
    phi[1] = 1;
    LL i,j;

    for(i=2;i<=TSz;i++)
    {
        if(!phi[i])
        {
            phi[i] = i-1;

            for(j=2*i;j<=TSz;j+=i)
            {
                if(!phi[j])
                {
                    phi[j] = j;
                }

                phi[j]/=i;
                phi[j]*=(i-1);
            }
        }
    }

    //for(i=1;i<=10;i++)cp(phi[i]);
}

LL ans[TSz+9];

void Table()
{
    LL i;
    ans[1] = 1;

    for(i=2;i<=TSz;i++)
    {
        ans[i] = ans[i-1] + 2*phi[i];
    }
}

int main()
{
    Euler_phi();
    Table();

    L num;

    while(~sf("%ld",&num) and num)
    {
        pf("%lld\n",ans[num]);
    }

    return 0;
}