Baekjoon #2417

#include<bits/stdc++.h>

using namespace std;
typedef long long ll;

bool chk(ll a, ll b) {
    if(b % a == 0) return a >= b / a;
    return a > b / a;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);

    ll N; cin >> N;
    if(N == 0) {
        cout << 0;
        return 0;
    }
    ll L = 1, R = 1LL << 32;
    while(L <= R) {
        ll mid = L + (R - L) / 2;
        if(chk(mid, N)) R = mid - 1;
        else L = mid + 1;
    }
    cout << L;

    return 0;
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
	public static void main(String[] args) throws IOException{
		FastReader rd = new FastReader();
		
		long n = rd.nextLong(), num = (long)Math.sqrt(n);
		System.out.print(num >= n ? num : num + 1);
	}
	
	static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while(st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() { return Integer.parseInt(next()); }
        long nextLong() { return Long.parseLong(next()); }
        double nextDouble() { return Double.parseDouble(next()); }
        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            }
            catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
}