/*
cf : F112
 /)  /)  ~ ┏━━━━━━━━━━━━━━━━━┓
( •-• )  ~ ♡ You are amazing ♡
/   づづ ~ ┗━━━━━━━━━━━━━━━━━┛
*/
#include <bits/stdc++.h>
using namespace std;

#define F first
#define S second
#define int long long
#define Ali ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)

const int N = 2e5 + 7;
const int MOD = 998244353;
const int P = 233;
const int inf = 1e18 + 7; 

int gcd(int x, int y){
	while(y){
		x %= y;
		swap(x, y);
	}
	return x;
}

int binpow(int n, int k){
	if (k == 0) return 1;
	if (k % 2 == 0){
		int val = binpow(n, k / 2);
		return (val * val) % MOD;
	}
	return (n * binpow(n, k - 1)) % MOD;
}

vector <int> t(N * 4), a(N, 1);

void build(int v, int l, int r){
	if (l == r){
		t[v] = a[l];
		return;
	}
	int mid = (r + l) / 2;
	build(v * 2, l, mid);
	build(v * 2 + 1, mid + 1, r);
	t[v] = t[v * 2] + t[v * 2 + 1];
}

void upd(int v, int l, int r, int x, int pos){
	if (l == r){
		t[v] = x;
		return;
	}
	int mid = (r + l) / 2;
	if (mid < pos) upd(v * 2 + 1, mid + 1, r, x, pos);
	else upd(v * 2, l, mid, x, pos);
	t[v] = t[v * 2] + t[v * 2 + 1];
}

int get(int v, int l, int r, int tl, int tr){
	if (l > tr || r < tl) return 0;
	if (tl <= l && r <= tr) return t[v];
	int mid = (l + r) / 2;
	return (get(v * 2, l, mid, tl, tr) + get(v * 2 + 1, mid + 1, r, tl, tr));
}

void abb() {
	int n;
	cin >> n;
	int x = sqrt(n);
	int ans = x * 2 - 1;
	if (x * (x + 1) <= n) ans++;
	cout << ans << "\n";
} 

signed main(){
	Ali;
    int T = 1; 
//    cin >> T;
    while(T--){
        abb();
    }
}