#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <sstream>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif
#define GET_MACRO(_1, _2, _3, NAME, ...) NAME
#define _rep(i, n) _rep2(i, 0, n)
#define _rep2(i, a, b) for(int i = (int)(a); i < (int)(b); i++)
#define rep(...) GET_MACRO(__VA_ARGS__, _rep2, _rep)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
using i64 = long long;
template<class T>
bool chmin(T& a, const T& b) { return (b < a) ? (a = b, true) : false; }
template<class T>
bool chmax(T& a, const T& b) { return (b > a) ? (a = b, true) : false; }

template<typename T>istream& operator>>(istream&i,vector<T>&v){rep(j,v.size())i>>v[j];return i;}
template<typename T>string join(vector<T>&v){stringstream s;rep(i,v.size())s<<' '<<v[i];return s.str().substr(1);}
template<typename T>ostream& operator<<(ostream&o,vector<T>&v){if(v.size())o<<join(v);return o;}
template<typename T>string join(vector<vector<T>>&vv){string s="\n";rep(i,vv.size())s+=join(vv[i])+"\n";return s;}
template<typename T>ostream& operator<<(ostream&o,vector<vector<T>>&vv){if(vv.size())o<<join(vv);return o;}

vector<bool> prime(7500, true);
vector<int> x(50000001);

void solve(int n)
{
    i64 ans = 0;
    iota(all(x), 0);
    for (int i = 4; i * i <= n; i += 2) prime[i] = false;
    for (int j = 4; j <= n; j *= 4)
    {
        for (int k = j; k <= n; k += j)
        {
            x[k] /= 4;
        }
    }
    for (int i = 3; i * i <= n; i += 2)
    {
        if (prime[i])
        {
            int w = i * i;
            for (i64 j = w; j * j <= n; j += i * 2)
            {
                prime[j] = false;
            }
            for (i64 j = w; j <= n; j *= w)
            {
                for (int k = j; k <= n; k += j)
                {
                    x[k] /= w;
                }
            }
            // cout << i << endl;
        }
    }
    for (int i = 1; i <= n; i++) ans += floor(sqrt(n / x[i]));
    cout << ans << endl;
}

int main()
{
    int n;
    cin >> n;
    solve(n);
}