Binary to Decimal INT

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _02.ConvertBinaryToDecimal
{
    class Program
    {
        // 02. Write a program to convert binary numbers to their decimal representation.

        static string ReadDecimalInput()
        {
            string input = "";
            bool boolean = true;
            while (boolean)
            {
                boolean = false;
                Console.Write("Insert binary number: ");
                input = Console.ReadLine();
                if (input.Length <= 32 && input != "")
                {
                    for (byte i = 0; i < input.Length; i++)
                    {
                        if (input[i] == '0' || input[i] == '1')
                        {
                        }
                        else
                        {
                            boolean = true;
                            input = "";
                            Console.WriteLine("Incorect input! Only '1' amd '0' allowed!");
                            break;
                        }
                    }
                }
                else if (input == "")
                {
                    Console.WriteLine("Empty input!");
                    boolean = true;
                }
                else
                {
                    Console.WriteLine("Incorect input! No more that 32 digits!");
                    boolean = true;
                }
            }

            return input;
        }

        static void BinaryToDecimal(string input)
        {
            int decNum = 0;

            if (input.Length == 32 && input[0] == '1') // negative
            {
                int j = input.Length - 2;
                int parse = 0;

                for (int i = 1; i < input.Length; i++, j--) // start from input[1] because input[0] holds the sign
                {
                    parse = int.Parse(input[i].ToString());
                    if (parse == 0)
                    {
                        decNum += 1 * (int)Math.Pow(2, j);
                    }
                }
                decNum = -decNum - 1;

            }
            else // positive
            {
                int j = input.Length - 1;
                int i = 0;
                int parse = 0;

                for (i = 0; i < input.Length; i++, j--)
                {
                    parse = int.Parse(input[i].ToString());
                    if (parse == 1)
                    {
                        decNum += 1 * (int)Math.Pow(2, j);
                    }
                }
            }
            Console.WriteLine(decNum);


        }

        static void Main(string[] args)
        {
            while (true)
            {
                string input = ReadDecimalInput();

                BinaryToDecimal(input);

                // check
                int n = Convert.ToInt32(input, 2);
                Console.WriteLine(n);
            }
        }
    }
}