using System;

namespace ConsoleApp1

{

    class Program

    {

        static void Main(string[] args)

        {

            //Console.WriteLine("enter a number");

            //string num = Console.ReadLine();

            //char currentChar;

            //double intNum = 0;

            //for (int i = 0; i < num.Length; i++)

            //{

            //    currentChar = num[i];

            //    intNum += (currentChar - 48) * Math.Pow(10, num.Length - 1 - i);

            //}

            //Console.WriteLine(Math.Sqrt(intNum));

​

            Console.WriteLine("enter a number");

            string num1 = Console.ReadLine();

            char currentChar1;

            double intNum1 = 0;

            int dotPlacement = -1;

            for (int i = 0; i < num1.Length; i++)

            {

                if (num1[i] == '.')

                    dotPlacement = i;

            }  

            if (dotPlacement != -1)

                {

                for (int i = 0; i < num1.Length; i++)

                {

                    currentChar1 = num1[i];

                    if (i < dotPlacement)

                        intNum1 += (currentChar1 - 48) * Math.Pow(10, dotPlacement - i - 1);

                    else if (i > dotPlacement)

                        intNum1 += (currentChar1 - 48) * Math.Pow(10, dotPlacement - i);

                }

                Console.WriteLine(intNum1-1);

            } 

            if (dotPlacement == -1)

            {

                for (int i = 0; i < num1.Length; i++)

                {

                    currentChar1 = num1[i];

                    intNum1 += (currentChar1 - 48) * Math.Pow(10, num1.Length - 1 - i);

                }

                Console.WriteLine(intNum1 - 1);

            }

​

        }

    }

}

​