Why output contain 'D' in C# program of ReadKey() ?

Question

 

using System;
using System.Collections.Generic;
using System.Text;

namespace CSharp5
{
    class Class3
    {
        static void Main()
        {
            ConsoleKeyInfo m = Console.ReadKey();
            Console.WriteLine("\n" + m.Key);
        }
    }
}

---

 

In Output screen, When I press 2, then it print D2. 

Why It prints D before output?