#include <fstream>
#include<cstdio>
using namespace std;
int mat[14][1000005];
int main()
{
    FILE *in,*out;
    in=fopen("fractii.in","r");
    out=fopen("fractii.out","w");
    int n;
    long long i,j,s,ind,cind;
    fscanf(in,"%d",&n);
    for(i=2;i<=n;i++)
    {
        if(mat[1][i]==0)
        {
            for(j=i+i;j<=n;j=j+i)
            {
                mat[1][j]++;
                mat[mat[1][j]+1][j]=i;
            }
        }
    }
    s=n;
    for(i=2;i<=n;i++)
    {
        if(mat[1][i]==0)
            s=s+n-n/i;
        else
        {
            ind=n;
            cind=n;
            for(j=2;j<=mat[1][i]+1;j++)
            {
                ind=ind/mat[j][i]*(mat[j][i]-1);
            }
            s=s+n-ind;
        }
    }
    fprintf(out,"%lld",s);
    return 0;
}