Above we denoted by S1 D1 the first symptom of the first disease - the order is taken from the "clauses" section, by S2 D1 the second symptom of the first disease, by S1 D2 the first symptom of the second disease a.s.o. In general, by Si Dj we denote the "i" symptom of the "j" disease. On the other hand, by Sn C3, n = 1..4, we noted the symptoms of the third category, category the disease from this example takes part of.