#include<bits/stdc++.h>

using namespace std;

long long i,n,ans = ;

template <typename T> inline void read(T &x) {

        long long f = ; x = ;

        char c = getchar();

        for (; !isdigit(c); c = getchar()) { if (c == '-') f = -f; }

        for (; isdigit(c); c = getchar()) x = (x << ) + (x << ) + c - '';

        x *= f;

}

template <typename T> inline void write(T x) {

    if (x < ) { putchar('-'); x = -x; }

    if (x > ) write(x/);

    putchar(x%+'');

}

template <typename T> inline void writeln(T x) {

    write(x);

    puts("");

}

int main() {

        read(n);

        for (i = ; i <= n; i++) ans += n / i;

        writeln(ans);

        return ;

}