PL/SQL PROGRAM

WRITE A PL/SQL BLOCK INPUT ANY STRING AND FIND OUT THE NUMBER OF WORDS IRRESPECTIVE OF THE SPACES?

DECLARE
STR   VARCHAR2(15):='&STR';
NO_OF_WORDS:=1;
BEGIN
FOR I IN 1..LENGTH(STR)
LOOP
IF(SUBSTR(STR,I,1)=' ' AND SUBSTR(STR,I+1,1)!=' ') THEN
NO_OF_WORDS:=NO_OF_WORDS+1;
END IF;
END LOOP;
DBMS_OUTPUT.PUT_LINE('THE NUMBER OF WORDS IN THE GIVEN STRING'||NO_OF_WORDS);
END;