Sharing (characters) is Caring! Overview
Consider the following task:

Given a positive integer n &gt; 0, output its integer square root. The integer square root of a number n is the largest value of x where x2 ≤ n, usually expressed with the formula floor(sqrt(n)).
Examples: 25 -&gt; 5, 24 -&gt; 4, 40 -&gt; 6, 1 -&gt; 1.

This task is easy enough on its own. However, in this challenge, your task is to solve this in as many languages as possible using a set of only 25 characters.
Example
First, you need to pick a set (no duplicates) of 25 bytes. It may look something like this (note the leading space):
 ()*-.05:=&gt;Mabdhilmnqrst|

Your challenge is then to, using only characters in this set, construct a solution to the problem in as many text based (sorry, Piet) languages as possible. You can use characters as many times as necessary, but you must not use characters outside the set.
The solutions can be either full programs or functions, but not snippets. For example, using this set of characters, I could do:
M -&gt; (int) Math.sqrt(M)    // Java (lambda expression)
M =&gt; Math.sqrt(M)|0        // Javascript (unnamed function)
lambda M: int(M**.5)       // Python (lambda function)

As I've used 3 languages, this would give me a score of 3.
Please also include the set of bytes you are using in your answer.
Rules

This is a rosetta-stone challenge - your score is the number of languages your submission includes. The highest score wins. Standard loopholes apply.
For this challenge, a 'language' counts as a distinctly different programming language - multiple versions of the same language (Python 2, Python 3, etc) are banned.
Programs only need to work for inputs within the language's standard integer range.
Programs with the exact same source code (polyglots) are not allowed.
To be more specific, it is a set of bytes, not characters - so you can use the 05AB1E £ and the Jelly ɱ as the same character (because they have the same codepoint).

Please don't feel as though you have to beat all other solutions - if you have an interesting answer, post it!
20 languages

Using  ()-#*.05;=&gt;^Vefikloqrst (24 characters) so far:

let f l=floor(l**0.5);;       OCaml
let f l=floor(l**0.5)         F#
f(l)=floor(l^.5)              Julia
f(o)=floor(o^.5)              PARI/GP
s^+&gt;5 0&gt;5 0*.5l               Pyth
(* **.5).floor                Perl 6
floor.(**0.5)                 Haskell
flr.(tt ^.5)                  Wonder
l=&gt;l**.5^0                    JavaScript
l-&gt;l**.5^0                    Cheddar
.5^5*5f                       Pyke
(isqrt)                       Maple
ri.5#i                        CJam
isqrt                         Common Lisp
0.5^k                         MATL
*.5^0                         Jelly
*.^0                          M
t0^                           05AB1E
q f                           Japt
r#                            Pushy
V-                            gs2