String Shuffling Interview Program using C#

public class Class1
{
    public static void Main()
    {
        Console.WriteLine("Enter the string");
        string sourcestring = Console.ReadLine().Trim().ToUpper();
        int rightIndex = sourcestring.Length - 1;
        int leftIndex = 0;
        StringBuilder resultentString = new StringBuilder();
        do {
            resultentString.Append(sourcestring[leftIndex]);
            leftIndex++;
            if (leftIndex > rightIndex) break;
            resultentString.Append(sourcestring[rightIndex]);
            rightIndex--;
        }
        while (leftIndex <= rightIndex);
        Console.WriteLine("Given string is : {0} and after shuffling the resultent string is {1}", sourcestring, resultentString.ToString());
        Console.ReadLine();
    }
}