How many times different letters appear in different words?
<p>How to know how many times strings s , t and n appear in each of the following words to have an output like this:</p>

<ul>
<li>descriptions: s 2 , t 1 , n 1</li>
<li>statements s 2 , t 3 , n 1</li>
</ul>

<p>The words are not known in advance.The first thing came to my mind was to make a dictionary, but for dictionaries we can only have two unknowns, so any hints how to approach it? 
Thanks in advance.</p>
