title: Count number of ways to climb a ladder with a twist
body: <p>I am aware of <a href="https://stackoverflow.com/questions/12255193/count-number-of-possible-paths-up-ladder">this</a> question.</p>
  
  <p>Question:</p>
  
  <p>A ladder has n steps. One can climb the ladder using any combination of steps of 1 or steps of 2. How many possible ways are there for one to climb the ladder?</p>
  
  <p>However, how will this number change if some of the stairs are broken?</p>
  
  <p>PS: This is not homework.</p>