The data set DRUGS contains data for a study of three drugs to treat a chronic condition (Agresti, 1990). Forty-six subjects receive drugs A, B, and C. The response to each is coded as favorable (F) or unfavorable (U). The data are recorded as cell counts instead of as one observation per patient. The variable Count contains the cell count. 
data drugs;
   input Drug_A $ Drug_B $ Drug_C $ Count @@;
   datalines;
F F F 6   F F U 16   F U F 2
F U U 4   U F F  2   U F U 4
U U F 6   U U U  6
;