N Items() is a function that has been a part of JMP for a long time. Check in the Scripting Index of your version of JMP to make sure it is there. I assume it will be. It is an essential component of being able to deal with JMP Lists.
Here is one way to count words and to count symbols
Names Default To Here( 1 );
str1 = "This is a test of the counting of words";
str2 = "Here is* a way to* count * symbols";
Show( "Counting Words", N Items( Words( str1, " " ) ) );
Show( "Counting Symbols", N Items( Words( str2, "*" ) ) );
Jim