/**
* I have heard his name is Po. Our fight will be legendary.
*												 Tai Lung
* 除了數學和資訊學，我討厭一切
*/

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
#include <chrono>
#include <random>
#include <unordered_map>

using namespace std;
using namespace chrono;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, int> pii;

#define cont        continue 
#define vd          void
#define fs          first
#define sc          second
#define mpii        map<int,int>
#define vi          vector<int>
#define vll         vector<ll>
#define db          double
#define no          cout<<"NO\n"
#define yes         cout<<"YES\n"
#define YN(b)		(b ? yes:no)
#define pb			push_back
#define all(x)		(x).begin(), (x).end()
#define uniq(x)		x.resize(unique(all(x)) - x.begin());
#define clock()		cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n"
#define testcase	int t; cin >> t; while(t--){solve(); if(t != 0) cout << "\n"; }
#define endl		'\n'
#define print		cout << 
#define scan		cin << 

const int N1 = 1e5 + 5;
const int N2 = 2e5 + 5;
const int N3 = 3e5 + 5;
const int N4 = 4e5 + 5;
const int N5 = 5e5 + 5;
const ll mod = 1e9 + 7;
const ll INF = 1e18 + 5;
const int N = 1e3 + 10;

const string alphabetl = "abcdefghijklmnopqrstuvwxyz";
const string alphabetu = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
mt19937_64 rng(chrono::steady_clock().now().time_since_epoch().count());

//void setIO(string str = "") {
//
//	if (str != "") {
//		freopen((str + ".in").c_str(), "r", stdin);
//		freopen((str + ".out").c_str(), "w", stdout);
//	}
//}

long long _add(long long a, long long b, long long modx) {
	if (a + b >= modx)
		return a + b - modx;
	else return a + b;
}

long long mult(long long a, long long b, long long modx) {
	return (a * b) % modx;
}

long long sub(long long a, long long b, long long modx)
{
	if (a - b < 0)
		return a - b + modx;
	else
		return a - b;
}

template <typename T>
void chmin(T& a, T b)
{
	a = min(a, b);
}

template <typename T>
void chmin1(T a, T& b)
{
	b = min(a, b);
}

template <typename T>
void chmax(T& a, T b)
{
	a = max(a, b);
}

template <typename T>
void chmax1(T a, T& b)
{
	b = max(a, b);
}


long long binPowByMod(long long a, long long b, long long modx)
{
	a %= modx;
	if (a == 0)
	{
		if (b == 0)
			return 1;
		else return 0;
	}
	if (b == 0)
		return 1;
	long long res = 1;
	while (b > 0)
	{
		if (b & 1)
			res = res * a % modx;
		a = a * a % modx;
		b >>= 1;
	}
	return res;
}

long long __gcd(long long a, long long b) { return b == 0 ? a : __gcd(b, a % b); }

long long lcm(long long a, long long b) { return (a * b) / __gcd(a, b); }

template <typename T>
void Cout(T x)
{
	cout << x << "\n";
	cout.flush();
	///////////////////
}

bool f(set<int>s, set<int>s1)
{
	for (auto i : s)
	{
		if (s1.count(i) == 0)
			return false;
	}
	return true;
}

inline void solve()
{
	ll n;
	cin >> n;

	ll s = sqrt(n);
	if (s * (s + 1) <= n)
		cout << 2 * s;
	else
		cout << 2 * s - 1;
}

int main()
{
	auto begin = std::chrono::high_resolution_clock::now();
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	//freopen("out", "r", stdin);
	//testcase;
	solve();
	cout << endl;
	auto end = std::chrono::high_resolution_clock::now();
	auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
	cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
	return 0;
}

//⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⣀⣀⣀⣀⣠⣼⠂⠀⠀⠀⠀⠙⣦⢀⠀⠀⠀⠀⠀⢶⣤⣀⣀⣀⣀⣀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣠⣴⣶⣿⣿⣿⣿⣿⣿⣿⣿⠷⢦⠀⣹⣶⣿⣦⣿⡘⣇⠀⠀⠀⢰⠾⣿⣿⣿⣟⣻⣿⣿⣿⣷⣦⣄⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣤⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⡟⠀⠀⠀⠀⢺⣿⣿⣿⣿⣿⣿⣿⣆⠀⠀⠀⠀⠀⠀⢹⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷⣦⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
//⠀⠀⠀⠀⠀⠀⠀⠀⢀⣴⢟⣥⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡇⠀⠀⠀⠀⢻⣿⣿⡏⢹⣿⣿⣿⣿⠀⠀⠀⠀⠀⠀⠀⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣮⣝⢷⣄⠀⠀⠀⠀⠀⠀⠀⠀
//⠀⠀⠀⠀⠀⠀⠀⣴⣿⣿⣿⣿⣿⣿⣿⣿⣿⡿⢛⣿⣿⣿⡇⠀⠀⠀⠀⠛⣿⣿⣷⡀⠘⢿⣧⣻⡷⠀⠀⠀⠀⠀⠀⣿⣿⣿⣟⢿⣿⣿⣿⣿⣿⣿⣿⣿⣝⢧⡀⠀⠀⠀⠀⠀⠀
//⠀⠀⠀⠀⠀⢠⣾⣿⠟⣡⣾⣿⣿⣧⣿⡿⣋⣴⣿⣿⣿⣿⣧⠀⠀⠀⠀⠀⢻⣿⣿⣿⣶⡄⠙⠛⠁⠀⠀⠀⠀⠀⢸⣿⣿⣿⣿⣷⣝⢻⣿⣟⣿⣿⣷⣮⡙⢿⣽⣆⠀⠀⠀⠀⠀
//⠀⠀⠀⠀⢀⡿⢋⣴⣿⣿⣿⣿⣿⣼⣯⣾⣿⣿⡿⣻⣿⣿⣿⣦⠀⠀⠀⠀⢀⣹⣿⣿⣿⣿⣶⣤⠀⠀⠀⠀⠀⣰⣿⣿⣿⣿⠻⣿⣿⣿⣮⣿⣿⣿⣿⣿⣿⣦⡙⢿⣇⠀⠀⠀⠀
//⠀⠀⠀⣠⡏⣰⣿⣿⡿⢿⣿⣿⣿⣿⣿⣿⡿⢋⣼⣿⣿⣿⣿⣿⣷⡤⠀⣠⣿⣿⣿⣿⣿⣿⣿⣿⣷⣄⠀⢠⣾⣿⣿⣿⣿⣿⣷⡜⢿⣿⣿⣿⣿⣿⣿⡿⠿⣿⣿⣦⡙⣦⠀⠀⠀
//⠀⠀⣰⢿⣿⣿⠟⠋⣠⣾⣿⣿⣿⣿⣿⠛⢡⣾⡿⢻⣿⣿⣿⣿⣿⣿⣿⣿⡿⠋⠻⣿⡟⣿⣿⣿⠻⢿⣿⣿⣿⣿⣿⣿⣿⣟⠻⣿⣆⠙⢿⣿⣿⣿⣿⣿⣦⡈⠻⣿⣿⣟⣧⠀⠀
//⠀⣰⢣⣿⡿⠃⣠⡾⠟⠁⠀⣸⣿⡟⠁⢀⣿⠋⢠⣿⡏⣿⣿⣿⣿⣿⢿⠁⢀⣠⣴⢿⣷⣿⣿⣿⠀⠀⠽⢻⣿⣿⣿⣿⡼⣿⡇⠈⢿⡆⠀⠻⣿⣧⠀⠈⠙⢿⣆⠈⠻⣿⣎⢧⠀
//⠀⢣⣿⠟⢀⡼⠋⠀⠀⢀⣴⠿⠋⠀⠀⣾⡟⠀⢸⣿⠙⣿⠃⠘⢿⡟⠀⣰⢻⠟⠻⣿⣿⣿⣿⣿⣀⠀⠀⠘⣿⠋⠀⣿⡇⣿⡇⠀⠸⣿⡄⠀⠈⠻⣷⣄⠀⠀⠙⢷⡀⠙⣿⣆⠁
//⢀⣿⡏⠀⡞⠁⢀⡠⠞⠋⠁⠀⠀⠀⠈⠉⠀⠀⠀⠿⠀⠈⠀⠀⠀⠀⠀⣿⣿⣰⣾⣿⣿⣿⣿⣿⣿⣤⠀⠀⠀⠀⠀⠉⠀⠸⠃⠀⠀⠈⠋⠀⠀⠀⠀⠙⠳⢤⣀⠀⠹⡄⠘⣿⡄
//⣸⡟⠀⣰⣿⠟⠋⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠛⠿⠿⠿⠟⠁⠀⠹⣿⣷⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠻⣿⣧⠀⢹⣷
//⣿⠃⢠⡿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢠⣄⣤⣀⠀⠀⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⢻⡇⠀⣿
//⣿⠀⢸⠅⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣰⡿⠋⠉⢻⣧⢀⣿⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⠀⢸
//⡇⠀⠈⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢿⣧⡀⠀⠀⣿⣾⡟⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠀⢸
//⢸⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠻⠿⣿⣿⠟⠋⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⡾
//⠈⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣰⡿⠋⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠃
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢰⡏⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⣧⢀⣾⣤⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⡼⣿⣿⣾⣤⣠⡼⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

//
//	░█████╗░░░░░░░░░░░░░░░
//	██╔══██╗░░██╗░░░░██╗░░
//  ██║░░╚═╝██████╗██████╗
//	██║░░██╗╚═██╔═╝╚═██╔═╝
//	╚█████╔╝░░╚═╝░░░░╚═╝░░
// ░╚════╝░░░░░░░░░░░░░░░
//