2. Design a regular language where every sentence has to start with any number of strings 11 (any number is none or more), then repeats 00 any number of times, then repeats 10 at least twice. Use regular expression notation. Clarification: alphabet is {0,1}. 'string' is the same as program in this context, but here the programs are written using the binary alphabet so strings here are binary; in regular expressions we use * for any number, + for one or more, for either and () for grouping. 3. For the above, how many valid strings there are? 4. For the above, how many valid strings are there if we restrict the total length to a) at most 6 bits