GetSFDCId

 using System;
using System.Text.RegularExpressions;

namespace sfchars {
    class Program {
        static void Main(string[] args) {
                        string suffix = string.Empty;

                        for (int i = 0; i < 3; i++) {
                                int flags = 0;

                                for (int f = 0; f < 5; f++) {
                                        string c = (args[0][i*5+f]).ToString();
                                        if (c.ToUpper() == c && Regex.IsMatch(c, @"[a-zA-Z]")) {
                                                flags = flags + (1 << f);
                                        }
                                }

                                if (flags <= 25) {
                                        suffix = suffix + "ABCDEFGHIJKLMNOPQRSTUVWXYZ"[flags];
                                } else {
                                        suffix = suffix + "012345"[flags - 26];
                                }
                        }
            Console.WriteLine(args[0] + suffix);
        }
    }
}