#include <stdio.h>

unsigned cmmdc(unsigned a, unsigned b) {
    if(b == 0)
        return a;
    return cmmdc(b, a % b);
}

int main(void) {
    freopen("fractii.in", "r", stdin);
    freopen("fractii.out", "w", stdout);
    unsigned n, count = 0, i, j;
    scanf("%u", &n);
    count = n;
    for(i = 2; i <= n; i++)
    {
        count++;
        for(j = 2 + !(i % 2); j <= n; j += 2)
            if(cmmdc(i, j) == 1)
                count++;
    }
    printf("%u", count);
    return 0;
}