Multiplication Sign

using System;

class MultiplicationSign
{
    static void Main()
    {
        double firstNumber = double.Parse(Console.ReadLine());
        double secondNumber = double.Parse(Console.ReadLine());
        double thirdNumber = double.Parse(Console.ReadLine());
        char sign = '0';

        if (firstNumber > 0)
        {
            sign = '+';
        }
        else
        {
            sign = '-';
        }

        if (secondNumber > 0 ^ sign == '+')
        {
            sign = '-';
        }
        else
        {
            sign = '+';
        }

        if (thirdNumber > 0 ^ sign == '+')
        {
            sign = '-';
        }
        else
        {
            sign = '+';
        }

        if (firstNumber == 0 || secondNumber == 0 || thirdNumber == 0)
        {
            sign = '0';
        }

        Console.WriteLine(sign);

    }
}