<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def prepare_data(problem, hparams, params, config):
 """Construct input pipeline."""

  input_fn = problem.make_estimator_input_fn(
      tf.estimator.ModeKeys.EVAL, hparams, force_repeat=True)
  dataset = input_fn(params, config)
  features, _ = dataset.make_one_shot_iterator().get_next()
  inputs, labels = features["targets"], features["inputs"]
  inputs = tf.to_float(inputs)
  input_shape = inputs.shape.as_list()
  inputs = tf.reshape(inputs, [hparams.batch_size] + input_shape[1:])
  labels = tf.reshape(labels, [hparams.batch_size])
  return inputs, labels, features