Fix typo.

Thou shalt not count to two unless proceeding to the number three.

Doc/tut/tut.tex

@@ -199,7 +199,7 @@ commands interactively; when called with a file name argument or with
 a file as standard input, it reads and executes a \emph{script} from
 that file. 
 
-A third way of starting the interpreter is
+A second way of starting the interpreter is
 \samp{\program{python} \programopt{-c} \var{command} [arg] ...}, which
 executes the statement(s) in \var{command}, analogous to the shell's
 \programopt{-c} option.  Since Python statements often contain spaces