I am dealing with a problem in which I have to label the inputs (in a sequence format) to 5 distinct classes. The input would be like: `X = {x_1,_x_2,...,X_500}` and the output should be something like: `Y = {Y_1,Y_2,...,Y_500}` But the problem is that too many of the labels are from the first class so a sample output would have many first class labels and only a few (5 or 6 samples) related to other classes. The classifier tends to learn to classify everything to first class and yet get higher accuracy which is not correct. What are your suggestions?