MultiplicationSign

using System;

class MultiplicationSign
{
    private static int GetInt(string intName)
    {
        while (true)
        {
            Console.Write("Enter " + intName + ": ");
            string str = Console.ReadLine();
            int i;
            bool isSuccessful = int.TryParse(str, out i);
            if (isSuccessful)
                return i;
        }
    }

    static void Main(string[] args)
    {
        int a = GetInt("a");
        int b = GetInt("b");
        int c = GetInt("c");

        if ( (a & (b & c)) == 0) {
            Console.WriteLine("0");
        }
        else if (((a ^ (b ^ c)) < 0) ||
                 ((b ^ (a ^ c)) < 0) ||
                 ((c ^ (a ^ b)) < 0)) {
            Console.WriteLine("-");
        }
        else {
            Console.WriteLine("+");
        }
    }
}