input: from typing import List
  
  def compute_3_layer_nn_output(input_layer: List[float], hidden_layer: List[List[float]], output_layer: List[float]) -> float:
      """Compute the output of a 3-layer artificial neural network given input layer, hidden layer, and output layer matrices.
      >>> compute_3_layer_nn_output([2, 3], [[0.1, 0.4], [0.8, 0.6], [0.3, 0.9]], [0.3, 0.7])
      0.73
      """
output:     hidden_layer_output = []
      for neuron in hidden_layer:
          neuron_output = sum(w * x for w, x in zip(neuron, input_layer))
          hidden_layer_output.append(neuron_output)
      
      output = sum(w * x for w, x in zip(output_layer, hidden_layer_output))
      return round(output, 2)