You will be shown a paragraph from a biomedical research article. Your task is to extract all drug combinations appearing in a specific sentence within in the paragraph. Each drug combination should be assigned to one of the following three categories:

- POS: Indicates a positive interaction between the drugs in the combination; for instance, drugs that have an additive or synergistic effect.
- NEG: Indicates a negative interaction between the drugs in the combination; for instance, combining these drugs might result in adverse side effects, or might reduce their efficacy.
- COMB: Indicates that the drugs are given in combination, but the type of interaction between the drugs cannot be determined based on the provided context.

Please format your answer as a json array. Each entry in the array should itself be an array formatted as [<drug_1>, <drug_2>, ..., <drug_n>, <category>] where <category> is one of the three categories listed above and <drug_1>, ..., <drug_n> are drug names copied verbatim from the input sentence. Different combinations may involve different numbers of drugs; in other words, the `n` in <drug_n> may vary.

As an example, the following output describes two extracted drug combinations; one between two drugs, and one between three drugs:

[["artesunate", "artemether", "COMB"], ["Nifedipine", "Labetalol", "Prazosin", "POS"]]

The paragraph and specific sentence are below. You should only extract relationships expressed in the specific sentence; the paragraph is provided for context.

In your output, return only the json array and no other text. If no drug combinations appear, return an empty array `[]`.

paragraph: Nifuratel-containing initial anti-Helicobacter pylori triple therapy in children. Proton pump inhibitor-containing triple therapy with amoxicillin and metronidazole is recommended as initial treatment of Helicobacter pylori in childhood. However, eradication rate with this "classic" regimen is relatively low in Russia. ### aim To evaluate empiric nifuratel , amoxicillin , and bismuth triple therapy for H. pylori gastritis in childhood . ### Materials And Methods Pediatric outpatients with H. pylori-associated chronic gastritis who underwent endoscopy for dyspeptic symptoms received the combination of bismuth subcitrate (8 mg/kg/day, q.d.s.), nifuratel (30 mg/kg/day, q.d.s.), and amoxicillin (50 mg/kg/day, q.d.s.) for 10 days. H. pylori status was determined before and after the treatment (in 4-6 weeks) by modified Giemsa staining. ### results Seventy-three children (48 boys, 25 girls, age range 9-14) were entered. H. pylori was eradicated in 63 patients (86%; 95% confidence interval: 76.6-93.2; intention-to-treat and per protocol). There were no serious adverse reactions and were no withdrawals due to any side-effects. All of side-effects were self-limiting (dark stools, urine discoloration, blackening of the tongue, and others). ### conclusions The combination of nifuratel, bismuth subcitrate, and amoxicillin was an effective and tolerable regimen for H. pylori eradication.

sentence: To evaluate empiric nifuratel , amoxicillin , and bismuth triple therapy for H. pylori gastritis in childhood .
[["nifuratel", "amoxicillin", "bismuth", "POS"]]