The output size of the last layer (18) doesn’t match the number of classes (38) in patternet

Hi

I used patternnet toolbox for classification problem However, The output size of the last layer is 18 which doesn’t match the number of classes which is 38 classes.

what should i change?

This is my code

hiddenLayerSize =2;

net = patternnet(hiddenLayerSize, trainFcn);

Thank you