How many entities exist in the following document? write a number

$\backslash$table$[[$Registration form$],[$Student Name:$],[$Student ID:$],[$Major:$],[$Address:$,$Date:$],[\backslash$table$[[$Course$],[$code$]],\backslash$table$[[$Course$],[$name$]],\backslash$table$[[$Course$],[$credit$]],$Section,$\backslash$table$[[$Course$],[$date$]]],[,,,,],[,,,,],[,,,,],[,$Tot,redit,,$]]$