using System;

namespace R2
{
    class Program
    {
        static void Main(string[] args)
        {
            // Declaratie van de variabelen
            int intR1, intR2, intS1;

            // De 2 getallen opvragen
            Console.Write("R1: ");
            intR1 = Convert.ToInt16(Console.ReadLine());

            Console.Write("S1: ");
            intS1 = Convert.ToInt16(Console.ReadLine());

            // De som berekenen
            intR2 = (intS1 * 2) - intR1;

            Console.WriteLine("R2 bedraagt " + intR2.ToString());
            Console.ReadLine();
        }
    }
}