using System;
using System.Numerics;
using System.Globalization;
public class FormatBigInt
{
public static void Main()
{
NumberFormatInfo fmtNum = new NumberFormatInfo();
fmtNum.NegativeSign = "~";
BigInteger number = BigInteger.Parse("~9999999999999", fmtNum);
Console.WriteLine(number.ToString(fmtNum));
Console.WriteLine(number);
}
}