match "shAzAm" with .*, can't find A, backtrack.
   match "shAzA"  with .*, can't find A, backtrack.
   match "shAz"   with .*
   match "shAzA"  with .*A
   match "shAzAm" with .*A.*, can't find A, backtrack
   match "shAzA"  with .*A.*, can't find A, backtrack
   match "shA"    with .*, can't find A, backtrack
   match "sh"     with .*
   match "shA"    with .*A
   match "shAzAm" with .*A.*, can't find A, backtrack,