title: VGG16 transfer learning
body: <p>When I try to implement transfer learning to train my ConvNet model, there's a snippet of code that I don't understand in this Keras blog (goo.gl/N60H13). In total, VGG16 has 21 layers, but in order to freeze all the other layers than the final FC, the number of the layers that I need to freeze would be 20. Does anyone understand why the blog made it to be 24 ([:25])?</p>
  
  <p>The code:</p>
  
  <pre><code>for layer in model.layers[:25]:
      layer.trainable = False
  </code></pre>