#include<cstdio>

int N, SUM;


int main()
{
    //freopen("fractii.in", "r", stdin);
    //freopen("fractii.out", "w", stdout);

    scanf("%d", &N);

    SUM += N;

    for(int i = 2; i <= N; i++)
    {
        SUM += (N - N/i);
        for(int j = 2; j < i; j++)
        {
            if(i%j == 0)
            SUM--;
        }
    }


    printf("%d\n", SUM);
    return 0;
}