\begin{array}{c} \color{lightblue}{\texttt{#Ileveledupalone}} \end{array}

`C++`

#include <iostream>
#include <fstream>
using namespace std;

int main()
{
    ifstream fin("DAY.INP");
    ofstream fout("DAY.OUT");
    long long N;
    fin >> N;
    long long g = 1;
    long long c = 1;
    long long s = 1;
    while (N > c)
    {
        s += g;
        g++;
        c += g;
    }
    long long p = N - (c - g);
    if (g % 2 == 0)
    {
        fout << s + 2 * (p - 1) << endl;
    } else
    {
        fout << s + 2 * (p - 1) + 1 << endl;
    }

    return 0;
}

#include <bits/stdc++.h>
using namespace std;
long long n, ans = 1, cnt = 1, mx = 1;
int main()
{
  cin >> n;
  while (mx < n)
  {
    if (cnt % 2 == 1)
    {
      ans += cnt / 2 + 1;
      mx++;
    }
    else 
    {
      ans += cnt / 2;
      mx++;
    }
    cnt++;
  }
  cout << ans;
}
// tdq