Alex received a data set with two classes. He plotted the data samples in the plot below. He plotted the data samples of each class with different markers and colors as indicated in the legend of his plot. Next, he trained a classifier to separate the data samples of class A from class B$.$ The classifier is shown with the white dashed line. Above the line is Class B$.$ How many data samples are there in Alex's dataset?

NOTE: type your answer in digits without any spaces or dots etc. E$.$g$.,1$