input: from typing import List
  
  def compute_3_layer_network(hidden_layer: List[List[float]], output_layer: List[float], input_layer: List[float]) -> float:
      """Compute the output of a 3-layer artificial neural network given the layers.
      The input layer and hidden layer are multiplied element-wise, and then the resultant
      is multiplied by the output layer to yield the final output.
  
      >>> compute_3_layer_network([[0.1, 0.4],[0.8, 0.6],[0.3, 0.9]], [0.3, 0.7], [2, 3])
      0.86
      >>> compute_3_layer_network([[0.2, 0.3],[0.4, 0.5],[0.6, 0.7]], [0.5, 0.6], [1, 2])
      0.85
      """
output:     hidden_output = [sum(a * b for a, b in zip(hidden_row, input_layer)) for hidden_row in hidden_layer]
      final_output = sum(a * b for a, b in zip(hidden_output, output_layer))
      return round(final_output, 2)