<form name="quickSearchForm" action="%SCRIPTURLPATH{view}%/%BASEWEB%/WebSearch">
   <input type="text" class="twikiInputField patternFormFieldDefaultColor" 
   name="search" value="%MAKETEXT{"Search"}%" size="14" 
   onfocus="clearDefaultandCSS(this);" onblur="setDefaultText(this);" />
   <input type="hidden" name="web" value="%BASEWEB%" />
   <input type="hidden" name="scope" value="all" />
   <input type="hidden" name="excludetopic" value="Test*" />
</form>

---

%CALC{"$REPLACE(AB1, -1, 1, 2)"}%

Result: AB2

%CALC{"$REPLACE(AB0, -1, 1, 2)"}%

Result: AB2