using System;
using System.Threading.Tasks;

namespace test_csharp
{
    static class Program
    {
        static Task<int> produce(int a, int b)
        {
            return Task.Factory.StartNew(() => { return a + b; });
        }

        static void Main(string[] args)
        {
            Task<int> f1 = produce(10, 15);
            Task<int> f2 = produce(15, 20);
            int r = f1.Result + f2.Result;
            Console.WriteLine("Result={0}\n", r);
        }
    }
}