Which product pairs (triplets, quadruplets) were most frequently purchased together? (original question)

I'm wondering if there are possible ways that I can count the patterns of the same products that are purchased through the same customer (Receipt). For instance, if CustomerID 5 and 9 both purchased bread and butter, the counts for the product pairs would be 2 in total.

\begin{tabular}{|c|c|c|c|c|} \hline & A & B & C & D \\ \hline 1 & Customer (Receipt) & Purchased Item & Purchase Price & \\ \hline 2 & 1 & Bread & 2.5 & \\ \hline 3 & 1 & Bread & 2.5 & \\ \hline 4 & 1 & Bread & 2.5 & \\ \hline 5 & 2 & Coffee & 8 & \\ \hline 6 & 2 & Coffee & 8 & \\ \hline 7 & 2 & Coffee & 8 & \\ \hline 8 & 2 & Coffee & 8 & \\ \hline 9 & 3 & Cheese & 3 & \\ \hline 10 & 3 & Cheese & 3 & \\ \hline 11 & 3 & Vegetables & 3 & \\ \hline 12 & 4 & Candy & 3.4 & \\ \hline 13 & 5 & Chips & 3 & \\ \hline 14 & 5 & Chips & 3 & \\ \hline 15 & 5 & Bread & 2.5 & \\ \hline 16 & 6 & Bread & 2.5 & \\ \hline 17 & 7 & Milk & 2.5 & \\ \hline 18 & 8 & Bread & 2.5 & \\ \hline 19 & 8 & Water & 1 & \\ \hline 20 & 9 & Juice & 3.5 & \\ \hline 21 & 9 & Juice & 3.5 & \\ \hline 22 & 9 & Juice & 3.5 & \\ \hline 23 & 9 & Cookies & 3 & \\ \hline 24 & 9 & Meat & 2.8 & \\ \hline \end{tabular}