How to extract first name, middle name and last name in excel

This video tells you the way how to extract first name, middle name and last name in excel:
If only extract to first name and last name:
First name: =LEFT(B5,FIND(" ",B5)-1)
Last name: =RIGHT(B5,LEN(B5)-FIND(" ",B5,1))

If extract to first name, middle name and last name:
first name: =IF(B17="","",LEFT(TRIM(B17),FIND(" ",TRIM(B17))-1))
middle name: =IF(B17="","",IF(LEN(TRIM(B17))-LEN(SUBSTITUTE(TRIM(B17)," ",""))=1,"",MID(TRIM(B17),SEARCH(" ",TRIM(B17),1)+1,SEARCH(" ",TRIM(B17),SEARCH(" ",TRIM(B17),1)+1)-SEARCH(" ",TRIM(B17),1))))
last name: =IF(B17="","",IF(LEN(TRIM(B17))-LEN(SUBSTITUTE(TRIM(B17)," ",""))=1,RIGHT(B7,LEN(B7)-FIND(" ",B7,1)),IF(LEN(TRIM(B17))-LEN(SUBSTITUTE(TRIM(B17)," ",""))=2,RIGHT(TRIM(B17),LEN(TRIM(B17))-SEARCH(" ",TRIM(B17),SEARCH(" ",TRIM(B17),SEARCH(" ",TRIM(B17))+1))),"NA")))