title: vb.net: extract string from "a123" to "b123"
body: <p>i have a string that looks like this:</p>
  
  <p>sodjfoisdfsdf sdofij sodiosifosf fsdi  a123 sdfoi sdofi osdi foi sdofd oi b123 sdfoijsfdoifsdiosfdoifsoifsdofjssfdoji</p>
  
  <p>how do i extract everything from a123 to b123?</p>