#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define no cout << "NO" << "\n";
#define yes cout << "YES" << "\n";

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int n;
    cin >> n;

    set<ll> s; // To store unique values

    for (ll i = 1; i * i <= n; i++)
    {
        ll sq = i * i;
        if (sq <= n)
            s.insert(sq);

        ll semi = i * (i + 1);
        if (semi <= n)
            s.insert(semi);
    }

    cout << s.size() << "\n";

    return 0;
}