You're surprised? I've been using SAS at various work locations for well over 30 years now!
The LENGTH statement defines the variable lengths. An unformatted INPUT statement such as I used will read character data either until the first space or the length of the variable (SAS defaults to 8 bytes for character variables, which is why the LENGTH statement was needed). Numbers will be read until the first space (although SAS may do some truncation if the value exceeds normal limits for a numeric variable).