Qbasic (Find Area of Four Walls)

DECLARE FUNCTION AR(N, A, M)
INput "Enter the height"; h
Input "Enter the length"; l
Input "Enter the breadth"; b
Area = Ar(N, A, M)
Print "Area of fout walls"; Area
End

Function Ar(N,A, M)
Ar = 2*h*(l+b)
End Function