WRITE A PLSQL PROGRAM CHECK GIVEN NUMBER IS AMSTRONG NUMBER OR NOT?

DECLARE
N NUMBER:=&N;
S NUMBER:=0;
R NUMBER;
M NUMBER;
BEGIN
M:=N;
WHILE(N!=0) LOOP
R:=MOD(N,10);
S:=S+R*R*R;
N:=FLOOR(N/10);
END LOOP;
IF(M=S) THEN
DBMS_OUTPUT.PUT_LINE('GIVEN NUMBER IS AMSTRONG');
ELSE
DBMS_OUTPUT.PUT_LINE('GIVEN NUMBER IS NOT AMSTRONG');
END IF;
END;