title: Count the occurences of rows based on it's columns values
body: <p>I have this matrix:</p>
  
  <pre><code>1 1
  1 2
  2 1
  2 2
  </code></pre>
  
  <p>I want to count the occurrences of the row that have values 1 1 in it's columns. How do I do it?</p>