#include<stdio.h>
#include<vector>

int cmmdc(int a,int b)
{
    while(b)
    {
        int r=a%b;
        a=b;
        b=r;
    }
    return a;
}

using namespace std;
FILE *in,*out;
int N,cnt,i,j,contor=1;
bool prim[1000001];  //cele cu false sunt prime
int main()
{
    in=fopen("fractii.in","rt");
    out=fopen("fractii.out","wt");
    fscanf(in,"%d",&N);
   /* for(i=2;i<=N;i++)
        prim[i]=true;
    for(i=2;i<=N;i++)
    {
        if(prim[i])
        {
            for(j=i<<1;j<=N;j+=i)
                prim[j]=false;
            cnt++;
        }
    }*/
    for(i=2;i<=N;i++)
    {
        for(j=1;j<=i;j++)
        {
            if( cmmdc(i,j)==1)
                contor+=2;
        }
    }

    fprintf(out,"%d",contor);

    return 0;
}