Keep bill IDs when a count alone loses useful detail

billsByCustomer = {}
billByID = {}
foreach bill in bills {
    customer = bill.Customer
    if (not isKey(billsByCustomer,customer)) {
        billsByCustomer[customer] = []
    }
    billsByCustomer[customer] = billsByCustomer[customer] ++ [bill.BillNo]
    billByID[bill.BillNo] = bill
}
foreach id in billsByCustomer["Ahmed"] {
    originalBill = billByID[id]
}

A count such as Ahmed→18 cannot tell us which shops supplied the food. Ahmed’s saved IDs are [18,20,25,29] in original bill-number order. IDs are references, not item counts. Use a billByID dictionary to retrieve each record directly rather than rescanning the entire pile for every ID.

All-bill lists include Bill 25, even though it has no Food row. Keep original labels Advaith and Mohith from the cards; the spoken transcripts also use spellings such as Adwaith and Mohit. The examples use the supplied-card labels consistently.