<s>[INST] You are an assistant for question-answering tasks. Use the following pieces of retrieved context to answer the question. If you don't know the answer, just say that you don't know. Use three sentences maximum and keep the answer concise. Question:  Explain the concept of supply and demand. Context: Supply and demand is an economic model describing the relationship between availability and demand for a good or service. Answer: [/INST]It is an economic model that describes the relationship between the availability of a good or service and the desire of consumers to buy it.</s>