AREA AND PERIMETER IN PL/SQL

DECLARE
R NUMBER(5,2);
AR NUMBER(7,2);
PERI NUMBER(5,2);
CH NUMBER(2);
BEGIN
R:= :ENTER_RADIUS_OF_CIRCLE;
CH:= :ENTER_CHARACTER_1_OR_2;
IF(CH=1) THEN
PERI:= 2*3.14*R;
DBMS_OUTPUT.PUT_LINE('PERIMETER IS' || ' ' || PERI);
ELSE
IF(CH=2) THEN
AR:=3.14*R*R;
DBMS_OUTPUT.PUT_LINE('AREA IS' || AR);
END IF;
END IF;
END;