Guess the TV Theme Song Lyrics #3

First line is the tv show. 1969-1974. This show is about a large blended family of six children, with three boys and three girls and a maid. It was written by Frank Vol & Sherwood Schwartz. This theme song was first sung by the Peppermint Trolley Company (Paul Parrish, John Beland, Lois Fletcher) for the pilot and season one, but from season two onward, the main vocals were performed by the kids themselves.