#include <stdio.h>

int i, n, v[1000001], j, nr;

void cit()
{
        FILE *f=fopen("fractii.in", "r");
        fscanf(f, "%d", &n);
        fclose(f);
}

void tip()
{
        FILE *f=fopen("fractii.out", "w");
        fprintf(f, "%d\n", nr);
        fclose(f);
}

void fct()
{
for (i = 1; i <= n; ++i)
    v[i] = i-1;
  
for (i = 2; i <= n; ++i)
    for (j = 2*i; j <= n; j += i)
    v[j] -= v[i];
nr=0;
for(i=2;i<=n;i++)
  nr=nr+v[i];
nr=(nr*2)+1;
}

int main()
{
        cit();
        fct();
        tip();
        return 0;
}