MODULE Pars5;

FROM	InOut		IMPORT	Read, WriteString, WriteLn;

VAR	ch    		   : CHAR;


PROCEDURE error;

BEGIN
   WriteString ("Error in parsing");
   WriteLn;
   HALT
END error;


PROCEDURE A;

BEGIN
   IF  ch = "x"  THEN
      Read (ch)
   ELSIF  ch = "("  THEN
      Read (ch);
      A;
      WHILE  ch = "+"  DO
         Read (ch);
         A
      END;
      IF  ch = ")"  THEN  Read (ch)  ELSE  error  END
   ELSE
      error
   END
END A;
			      	  
BEGIN
   REPEAT
      Read (ch);
      A
   UNTIL  ch = '.';
   WriteString ("No errors in syntax!");
   WriteLn
END Pars5.