Graphic underneath shows a fenced area. The perimeter enclosure has a rectangular portion $($with $3$ sides, as shown$),$ connected to a semi$-$circular part. The cost to build and install the fence is $$\frac{15}{f}t$ for the curved portions of fence, and $$\frac{12}{f}t$ for the straight portions of fence.

Write a user$-$defined function, such that the code would:

a$)$ Consider $"R"$ and $"L"($where $L$ is the width of the rectangular part and $R$ is the radius of curvature of the curved portion$)$ as the input parameters to run the function. Choose any combination of $R$ and $L$ values.

b$)$ Calculate the output "cost" to build the enclosure fence.

c$)$ If the cost to build the enclosure exceeds $$1500,$ make the code write out "This is too expensive".

Otherwise, make the code write "The expenses are manageable".

$2+3+10=15$ points