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#include <iostream>
#include<fstream>
#include<vector>

using namespace std;
int isPrime(int a,vector<int> vect)
{
    for(int i=0;i<vect.size();i++)
    {
        if(a==vect.at(i))
            return 1;
    }
    return 0;
}
int main()
{
    int n;
    ifstream f("fractii.in");
    ofstream g("fractii.out");
    f>>n;
    vector<int> unu;
    int numere=n+(n-1);
    unu.push_back(2);
    int index=3;
    while(index<=n)
    {
        for(int i=0;i<unu.size();i++)
        {
            if(index%unu.at(i)==0)
            {
                break;
            }
            if(i==(unu.size()-1))
            {
                if(index%unu.at(i)!=0)
                {
                    unu.push_back(index);
                    break;
                }
            }
        }
        index+=1;
    }
    for(int i=2;i<=n;i++)
    {
        int ok = isPrime(i,unu);
        if(ok==1)
        {
            for(int k=i+1;k<=n;k++)
            {
                if(k%i!=0 )
                {
                    numere= numere +2;
                }
            }
        }
        else
        {
            for (int j=i+1;j<=n;j++)
            {
                bool bine=true;
                for(index=0;index<unu.size();index++)
                {
                    if(unu.at(index)<=i)
                    if(i%unu.at(index)==0 && j%unu.at(index)==0)
                    {
                        bine=false;
                    }
                }
                if(bine)
                {
                    numere+=2;
                }
                
            }
        }
    }
    
    g<<numere;
    f.close();
    g.close();
    return 0;
}