using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

        //Write the method: static double Sum(string input) such that

        //1) input will be a string that contains only numbers and the letter T

        //2) if a number has a T next to it then double the number and add it to the sum

        //3) if a number has two letter Ts next to it, then double the number and add it to the sum

        public static void Main(string[] args)

        {

            var tests = new List<TestCase>

            {

                new TestCase("1T", 2),

                new TestCase("1T5T5T11", -5)

            };

            foreach (var testCase in tests)

            {

                var acutal = Sum(testCase.Given);

                if (acutal != testCase.Expected)

                {

                    throw new Exception($"Incorrect. Expected:{testCase.Expected}, but got {acutal}");

                }

            }

            Console.WriteLine("success");

        }

​

        public class TestCase

        {

            public double Expected { get; }

            public string Given { get; }

            public TestCase(string given, double expected)

            {

                Given = given;

                Expected = expected;

            }

        }

​

        static double Sum(string input)

        {

            throw new NotImplementedException("your code here");

        }

}