Pizza, Pizza, Deep Dish Pizza! April 5th is National Deep DIsh Pizza Day, the theme of this challenge. Given a positive integer n (n is greater than 0), create an ASCII deep dish pizza. Actual deep dish pizza shown:



As you can see, there is a layer of crust on the bottom and surrounding the rest of the pizza. 

How to make the pizza

The crust is made of two layers. The first layer will be n tall and n*3 long. Length is the number of characters (including spaces) in the highest line. So given n is 1, the first layer would look like this:

\_/  1 character tall
 3 characters long


If n is two:

\    /   2 characters tall
 \__/
  6 characters long


Now for the second layer of the crust. It will go outside the first, inner crust so therefore, it will be n+2 characters tall and (n*3)+6) characters long. Given n is one:

\       /  3 characters tall
 \     /
  \___/
   9 characters long (3 underscores, 3 slashes on either side)


If n is two:

\          / 4 characters high
 \        /
  \      /
   \____/
    12 characters long


You would then match up the two highest pairs of \/ with each other for the inner and outer crust. In n is 1:

\ \   / /
 \ \_/ /
  \___/


If done correctly, it would look like a V without the tops with a one character difference between each layer. Speaking of tops, the crust will be joined together by a pair of /\, separated by a line of underscores (n*3)+2 long to complete the crust and pizza. 

Examples

If n is 1:

/\_____/\
\ \   / /
 \ \_/ /
  \___/


n is 2:

/\________/\
\ \      / /
 \ \    / /
  \ \__/ /
   \____/ 


n is 3:

/\___________/\
\ \         / /
 \ \       / /
  \ \     / /
   \ \___/ /
    \_____/


Winning Criterion

This is code-golf, so the shortest code in bytes wins!
JavaScript (ES6), 136 bytes



f=
n=&gt;"/\\"+(r=s=&gt;s[0][0].repeat(n-1)+s)`_`+r`_`+r`___/\\
`+r` `.replace(/ /g,"$`\\ \\$`   $'$'$'/ /\n")+r` \\ \\`+r`_/ /
`+r`  \\`+r`___/`
&lt;input type=number min=1 oninput=o.textContent=f(this.value)&gt;&lt;pre id=o&gt;




The whole pizza is very repetitious so the r function (designed as a tagged template literal) repeats the first character of its input n times. This handles the top and bottom two lines of the pizza. The middle is repeated by replacing a string of blanks; the $` and $' subsitutions automatically correspond to increasing and decreasing numbers of blanks thus positioning the \ \ and / / appropriately.