title: Counting number of same values in map
body: <p>is there any command that counts the number of same values in a map?</p>
  
  <p>like:</p>
  
  <pre><code>map&lt;int, string&gt; m;
  m[1] = "A";
  m[22] = "A";
  m[53] = "C";
  m[12] = "A";
  m[6] = "A";
  
  int count = m.count("A");// 4
  </code></pre>
  
  <p>or should i just write it myself, since its not too hard?</p>