I'm getting the error Error in eval(predvars, data, env) : object 'B' not found, I'm not sure how to do this line:

nn <- neuralnet(B M~ area texture smoothness, data=cancertrain, hidden=3,

B M are the two potential values, either benign or malignant, and the three attributes that have more impact in the determination are area, texture, and smoothness. I'm assuming I just have the parameters in the function neuralnet done incorrectly, does anyone know? Here's the