DEFINITION Input0; (*Access to keyboard and clock Implements a subset of basic module Input applicable to console applications. Import with Input := Input0 to emphasize the compatibility.*) VAR TimeUnit: INTEGER; (*clock ticks per second*) PROCEDURE Available(): INTEGER; (*returns the number of characters in the keyboard buffer*) PROCEDURE Read(VAR ch: CHAR); (*returns (and removes) the next character from the keyboard buffer. If the buffer is empty, Read waits until a key is pressed.*) PROCEDURE Time(): INTEGER; (*returns the time elapsed since system startup in units of size 1 / TimeUnit seconds*) END Input0.