When such values
appear in the lines of data, you must supply an appropriate informat for them. An informat is an
instruction which tells SAS how the corresponding variable should be interpreted. The informat
appears after the name of its variable in the INPUT statement and contains information about the
type of variable, the length of the variable, and interpretations of such characters as commas and
decimal points. Informats end with periods, to distinguish them from variable names.