#include<bits/stdc++.h>
using namespace std;


#define    boost        ios::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define    nl           "\n"
#define    ll           long long
#define    pb           push_back
#define    mpr          make_pair
#define    fr(i,a,n)   for(ll i=a;i<n;++i)
#define    fr0(i,n)     for(ll i=0;i<n;++i)
#define    pii          pair<ll, ll>
#define    mem(a)       memset(a,0,sizeof(a))
const ll mod = 1000000007;

void fio()
{
#ifndef ONLINE_JUDGE
    freopen("Input.txt", "r", stdin);
    freopen("o.txt", "w", stdout);
#endif
}

template<typename T> void TIME(T start, T end)
{
#ifndef ONLINE_JUDGE
    double time_taken =  chrono::duration_cast<chrono::nanoseconds>(end - start).count();
    time_taken *= 1e-9;
    cout << "\nExecuted in: " << fixed
         << time_taken << setprecision(9);
    cout << " sec";
#endif
}


const int MAX = 1000001; 
  
// array to store prime factors 
int factor[MAX] = { 0 }; 
  
// function to generate all prime factors 
// of numbers from 1 to 10^6 
void generatePrimeFactors() 
{ 
    factor[1] = 1; 
  
    // Initializes all the positions with their value. 
    for (int i = 2; i < MAX; i++) 
        factor[i] = i; 
  
    // Initializes all multiples of 2 with 2 
    for (int i = 4; i < MAX; i += 2) 
        factor[i] = 2; 
  
    // A modified version of Sieve of Eratosthenes to 
    // store the smallest prime factor that divides 
    // every number. 
    for (int i = 3; i * i < MAX; i++) { 
        // check if it has no prime factor. 
        if (factor[i] == i) { 
            // Initializes of j starting from i*i 
            for (int j = i * i; j < MAX; j += i) { 
                // if it has no prime factor before, then 
                // stores the smallest prime divisor 
                if (factor[j] == j) 
                    factor[j] = i; 
            } 
        } 
    } 
} 

int calculateNoOFactors(int n) 
{ 
    if (n == 1) 
        return 1; 
  
    int ans = 1; 
  
    // stores the smallest prime number 
    // that divides n 
    int dup = factor[n]; 
  
    // stores the count of number of times 
    // a prime number divides n. 
    int c = 1; 
  
    // reduces to the next number after prime 
    // factorization of n 
    int j = n / factor[n]; 
  
    // false when prime factorization is done 
    while (j != 1) { 
        // if the same prime number is dividing n, 
        // then we increase the count 
        if (factor[j] == dup) 
            c += 1; 
  
        /* if its a new prime factor that is factorizing n,  
           then we again set c=1 and change dup to the new  
           prime factor, and apply the formula explained  
           above. */
        else { 
            dup = factor[j]; 
            ans = ans * (c + 1); 
            c = 1; 
        } 
  
        // prime factorizes a number 
        j = j / factor[j]; 
    } 
  
    // for the last prime factor 
    ans = ans * (c + 1); 
  
    return ans; 
} 

void solve(){
    int n;
    cin>>n;
    generatePrimeFactors();
    int ans=0;
    for(int i=1;i<n;i++){
        int c =calculateNoOFactors(i);
        ans+= c;
        
    }
    
    cout<<ans;

}   


int main()
{
    //auto start = chrono::high_resolution_clock::now();
    boost;
    fio();
    ll t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }
    //auto end = chrono::high_resolution_clock::now();
    //TIME(start, end);
    return 0;
}

Measured memory_bytes: 7540