Trying to ""Count"" the number of selections in a multi-select text field

Leveraging Mark's awesome formula to pull the Sum...

var text value = ToText([MultiSelectFieldName]);
Sum(
ToNumber(Trim(Part($value,1,";"))),
ToNumber(Trim(Part($value,2,";"))),
ToNumber(Trim(Part($value,3,";"))),
ToNumber(Trim(Part($value,4,";"))),
ToNumber(Trim(Part($value,5,";"))),
ToNumber(Trim(Part($value,6,";"))),
ToNumber(Trim(Part($value,7,";"))),
ToNumber(Trim(Part($value,8,";"))),
ToNumber(Trim(Part($value,9,";"))),
ToNumber(Trim(Part($value,10,";"))),
ToNumber(Trim(Part($value,11,";"))),
ToNumber(Trim(Part($value,12,";"))),
ToNumber(Trim(Part($value,13,";"))),
ToNumber(Trim(Part($value,14,";"))),
ToNumber(Trim(Part($value,15,";"))),
ToNumber(Trim(Part($value,16,";"))),
ToNumber(Trim(Part($value,17,";"))),
ToNumber(Trim(Part($value,18,";"))),
ToNumber(Trim(Part($value,19,";"))),
ToNumber(Trim(Part($value,20,";")))
)