import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        long n = sc.nextLong();
        long sqrt = getSqrt(n);
        long ans = sqrt * 2;
        if (sqrt * sqrt == n) {
            ans--;
        }
        System.out.println(ans);
    }
    
    static long getSqrt(long x) {
        long left = 0;
        long right = Integer.MAX_VALUE;
        while (right - left > 1) {
            long m = (left + right) / 2;
            if (m * m <= x) {
                left = m;
            } else {
                right = m;
            }
        }
        return left;
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}