Markov Chain Algorithm Generate Text
        Given a sentence: my dog is black and my cat is white, my cat eats my dog.
            
            prefix          suffix
            "" ""           my
            "" my           dog
            my dog          is
            dog is          black
            is black        and
            black and       my
            and my          cat
            my cat          is
            cat is          white
            is white        my
            white my        cat
            my cat          eats
            cat eats        my
            eats my         dog
            

        Input: prefix and suffix.
        prefix: my cat        
        suffix: is 
        remove the first word from the prefix and use the suffix word as 
        new prefix: cat is

            
            prefix: cat is   -> white
            prefix: is white -> my
            prefix: white my -> cat
            prefix: my cat   -> eats
            prefix: cat eats -> my
            prefix: eats my  -> dog
            prefix: my dog   -> is
            prefix: dog is   -> black
            prefix: is black -> and
            end if the number of words hit certain limit or no suffix is founded.