#include <stdio.h>
int cmmdc (int a, int b)
{
   
    while (b) {
         int r = a % b;
        a = b;
        b = r;
     
    }
   return a;
}

int main()
{
    int n, sum = 0;
    FILE *f = fopen("fractii.in", "r");
    FILE *f1 = fopen("fractii.out", "w");
    fscanf(f, "%d", &n);
    sum = 2 * (n / 2- 1);
    for (int i = 1; i  <= n / 4; i++)
    for (int j = 1; j <= n / 2; j++) {
        if(cmmdc(i, j) == 1)
        sum = sum + 2;
    }
    fprintf(f1, "%d", sum);
    fclose(f);
    fclose(f1);
}