Problem U

#include<iostream>
#include<cmath>
#include<iomanip>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<vector>
#include<utility>

#define ll long long
#define nl '\n'
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define rall(s)  s.rbegin(), s.rend()
#define ceill(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
using namespace std;

void Fast_IO(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
    #endif
}





void solve(){

double n;  cin >> n;
    ll res = 0;
    for(int i = 1; i <= ceil(cbrt(n)); i++)
        for(int j = i; i*j <= n; j++){
            ll y = n /i/j;
            if(y >= j){
             res += y-j+1;
           }else break;
        }
    cout << res ;



}

int main(){
    Fast_IO();
int t =1;
//cin>>t;
while(t--){
solve();
}
return 0;
}