#include <iostream>
#include <complex>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
#include <random>
#include <iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef pair<ll,ll> P;
const ll MOD=1000000007;
const ll MAX_N=500010;
const ll INF=999999999999;
map<ll,ll> mp;

void bunkai(ll n){
    for(ll i=2;i*i<=n;i++){
        while(n%i==0){
            n/=i;
            mp[i]++;
        }
    }
    if(n!=1) mp[n]++;
}

int main(){
    ll n;
    cin>>n;
    if(n>=9750000){
        ll ans=796016413077051;
        for(ll k=9750001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=9500000){
        ll ans=754546104527913;
        for(ll k=9500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=9250000){
        ll ans=714214048734419;
        for(ll k=9250001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=9000000){
        ll ans=675021515919670;
        for(ll k=9000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=8750000){
        ll ans=636961255455435;
        for(ll k=8750001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=8500000){
        ll ans=600036645526326;
        for(ll k=8500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=8250000){
        ll ans=564243999095306;
        for(ll k=8250001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=8000000){
        ll ans=529581632274134;
        for(ll k=8000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=7750000){
        ll ans=496045307801936;
        for(ll k=7750001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=7500000){
        ll ans=463635895079489;
        for(ll k=7500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=7250000){
        ll ans=432351372593538;
        for(ll k=7250001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=7000000){
        ll ans=402188826344049;
        for(ll k=7000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=6750000){
        ll ans=373145655996233;
        for(ll k=6750001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=6500000){
        ll ans=345219904513529;
        for(ll k=6500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=6250000){
        ll ans=318409439232054;
        for(ll k=6250001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=6000000){
        ll ans=292711324081941;
        for(ll k=6000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=5750000){
        ll ans=268122443879733;
        for(ll k=5750001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=5500000){
        ll ans=244642548171917;
        for(ll k=5500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=5250000){
        ll ans=222266481117362;
        for(ll k=5250001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=5000000){
        ll ans=200992441246692;
        for(ll k=5000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=4500000){
        ll ans=161737467121483;
        for(ll k=4500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }

    if(n>=4000000){
        ll ans=126850549017804;
        for(ll k=4000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }

    if(n>=3500000){
        ll ans=96301520878991;
        for(ll k=3500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=3000000){
        ll ans=70058785460280;
        for(ll k=3000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    
    if(n>=2500000){
        ll ans=48081994935671;
        for(ll k=2500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=2000000){
        ll ans=30326413365285;
        for(ll k=2000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    if(n>=1000000){
        ll ans=7235062807366;
        for(ll k=1000001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }

    if(n>=500000){
        ll ans=1722125036282;
        for(ll k=500001;k<=n;k++){
            mp.clear();
            bunkai(k);
            ll buf=k;
            for(auto p:mp){
                buf*=(p.second+1);
            }
            ans+=buf;
        }
        cout<<ans<<endl;
        return 0;
    }
    
    ll ans=0;
    for(ll k=1;k<=n;k++){
        mp.clear();
        bunkai(k);
        ll buf=k;
        for(auto p:mp){
            buf*=(p.second+1);
        }
        ans+=buf;
    }
    cout<<ans<<endl;
}

Measured memory_bytes: 3636