INPUT FILE

The input file(s) have either a 'fixed-format' or 'free-format'
header.  Pulse times of arrival (TOAs) follow the header, or may
be listed in a separate file if a free-format header is used.
Use of the fixed-format headers is discouraged, as new features will likely
be added only for free-format files.

Blank lines and comment lines are allowed throughout input files
except within fixed-format headers.  Comment lines are indicated
by 'C ' (capital C followed by a space) in the first two columns
or by '#' in the first non-blank column.