=ARRAYFORMULA(COUNTA(IFERROR(SPLIT(REPT("×"&
REGEXEXTRACT(TRANSPOSE(SPLIT(B1, ",")), "\d+"), NETWORKDAYS(
REGEXEXTRACT(TRANSPOSE(SPLIT(B1, ",")), "\d+"),
REGEXEXTRACT(TRANSPOSE(SPLIT(B1, ",")), "-.(\d+)"))+1), "×"))))
=ARRAYFORMULA(COUNTA(IFERROR(SPLIT(REPT("×"&
REGEXEXTRACT(TRANSPOSE(SPLIT(A1, ",")), "\d+"), NETWORKDAYS(
REGEXEXTRACT(TRANSPOSE(SPLIT(A1, ",")), "\d+"),
REGEXEXTRACT(TRANSPOSE(SPLIT(A1, ",")), "-.(\d+)"))+1), "×"), "")))