Program to find area if 4 walls using FUNCTION

DECLARE FUNCTION AREA(L,B,H)
CLS
INPUT"ENTER LENGTH";L
INPUT"ENTER BREADTH";B
INPUT"ENTER HEIGHT";H
AR=AREA
PRINT"Area of 4 walls=";AREA(L,B,H)
END

FUNCTION AREA(L,B,H)
AREA=2*H*(L+B)
END FUNCTION