#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n,s,i,j,np=0,aux,prod,fi=0;
    char *v,*p;
    FILE *f,*g;
    f=fopen("fractii.in","r");
    g=fopen("fractii.out","w");
    fscanf(f,"%d",&n);
    v=(char*)malloc(n+1);
    for(i=2;i<n;i++)
    {
        v[i]=1;
    }
    for(i=2;i*i<=n;i++)
    {
        if(v[i])
        {
            for(j=i;j<=n/i;j++)
            {
                v[i*j]=0;
            }
        }
    }
    for(i=2;i<=n;i++)
    {
        if(v[i])
        {
            np++;
        }
    }
    p=(int*)malloc(np*sizeof(int));
    j=0;
    for(i=2;i<=n;i++)
    {
        if(v[i])
        {
            p[j]=i;
            j++;
        }
    }
    free(v);
    for(i=2;i<=n;i++)
    {
        prod=1;
        aux=i;
        for(j=0;j<np && p[j]<=i && aux>1;j++)
        {
            if(aux%p[j]==0)
            {
                prod=prod*(p[j]-1);
                aux=aux/p[j];
            }
            while(aux%p[j]==0)
            {
                prod=prod*p[j];
                aux=aux/p[j];
            }
        }
        fi=fi+prod;
    }
    fi=(fi<<1)+1;
    printf("%d",fi);
    free(p);
    fclose(f);
    fclose(g);
    return 0;
}