def _get_rf_size_node_input(stride, kernel_size, rf_size_output):
  """Computes RF size at the input of a given layer.

  Args:
    stride: Stride of given layer (integer).
    kernel_size: Kernel size of given layer (integer).
    rf_size_output: RF size at output of given layer (integer).

  Returns:
    rf_size_input: RF size at input of given layer (integer).
  """
  return stride * rf_size_output + kernel_size - stride