Area of a box.(FUNCTION)

DECLARE FUNCTION AREA(L,B,H)
CLS
INPUT"ENTER LENGTH";L
INPUT"ENTER BREADTH";B
INPUT"ENTER HEIGHT";H
PRINT"THE AREA OF BOX IS ";AREA(L,B,H)
END

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