using System;

public class Program

{

    public static void Main()

    {

        string nline = Console.ReadLine();

        int n = int.Parse (nline);

          int result = Findsqrt(n);

​

            Console.WriteLine(result);

    }

    public static int Findsqrt (int n)

    {

        int result =0;

        for (int i=1; i <= n*n; i++)

        {

            if (i*i>=n)

            {

                if ( ((i*i)-n) < (n - ((i-1)*(i-1))) )

                {

                result = i;

                }

                else 

                {   

                result = i-1;

                }

                break;

            }

        }

        return result;

    }

}