Formula to count Alpha Cells

I am trying to count the number of cells that have alpha data in a column.

Column E has either RN, EN or AIN. Column F has alpha data in some rows. I would like a count of how many cells in Column F have data where Column E has RN ... or EN or AIN

I have used =COUNTIFS(E:E,"*RN*",F:F,"<>") but this only works sometimes? and I cannot use the constant $E:$E to be able to copy that formula to columns G, H I etc.

Thanks