Chicago 25 or 6 to 4

Chicago : 25 or 6-2-4
25 or 6 to 4" is a song written by American musician Robbert Lamm, one of the founding members of the band Chicago, It was recorded in August 1969 for their second album, Chicago, with Peter Cetera on lead vocals and released as a single in June 1970.
Lamm said the song is about trying to write a song in the middle of the night. The song's title is the time at which the song is set: 25 or 26 minutes before 4 a.m., phrased as, "twenty-five or [twenty-]six [minutes] to four [o’clock]," (i.e. 03:35 or 03:34). Because of the unique phrasing of the song's title, "25 or 6 to 4" has been interpreted to mean everything from a quantity of illicit drugs to the name of a famous person in code.
The guitar solo by Terry Kath is exceptional and recognised as one the best although his exceptional talent is often overlooked and unfortunately he died from drug misuse ant a young age