title: How to set input shape of a GRU/LSTM
body: <p>I am trying to train my model to predict the next number in an integer sequence. The integer sequence that I created was generated in random.
  My X_train = [[1,2,3,4,5,6], [45,45,46,47,48,49], [203,204,205,206,207,208]...]
  and Y_train = [[7,8,9], [50,51,52], [209,210,211]]
  The shape of <code>X_train = (10000,6,511)</code> and <code>Y_train = (10000,3,511)</code> 
  How should I set my input shape for my GRU/LSTM model?</p>
  
  <pre><code>def define_models(n_input = 6, n_output = 3):
      # define training encoder
      sequence = Input(shape=(n_input,), dtype="int32")
      embedded = Embedding(13, 300, mask_zero=True)(sequence)
      gru1 = GRU(1000, return_sequences=True)(embedded)
      after_dp = Dropout(0.5)(gru1)
      gru2 = GRU(1000, return_sequences=True)(after_dp)
      after_dp = Dropout(0.5)(gru2)
      output = TimeDistributed(Dense(13, activation="softmax"))(after_dp)
  
      model = Model(input=sequence, output=output)
  
      return model
  </code></pre>
  
  <p>i am getting the error :</p>
  
  <pre><code>ValueError: Error when checking input: expected input_1 to have 2 dimensions, but got array with shape (10000, 6, 511)
  </code></pre>
  
  <p>How should I fix it for my dataset?</p>