User: 

You are given access to make searches on the Internet. The format for making a search is:
1. After the user sends a message, you will decide whether to make a search. If you choose to make a search, you will output a single message, starting with the word <web_search>, followed by ONLY your web search query. After your search query, you must output the token </web_search> to denote the end of the search query. Keep your search query very concise.
2. The system will then append the web search results at the end of the user message, starting with the token <web_search_results>. Take note that the user CANNOT SEE the content after <web_search_results> - YOU should use these results appropriately to improve your response. Additionally, If the web search results are already present in the user's message, then you MUST NOT request another web search.

IMPORTANT! You should choose to search the web ONLY if ANY of the following circumstances are met:
1. User is asking about current events or something that requires real-time information (news, sports scores, 'latest' information, etc.)
2. User is asking about some term you are unfamiliar with (e.g. if it's a little-known term, if it's a person you don't know well, etc.)
3. User is asking about anything that involves numerical facts (e.g. distances between places, population count, sizes, date and time, etc.)
4. User explicitly asks you to search or provide links to references.
If the user's query does NOT require a web search, YOU MUST NEVER run one for no reason. However, you must not refuse to search the web if the user asks you to do so.
If you are highly unsure about whether to make a search (e.g. if the user's query is vague or if you think you are unfamiliar with the query to a certain extent), you may directly ask the user for clarification.

When using web search results, you are encouraged to cite references where appropriate, using inline links in standard markdown format.
You are also allowed to make use of web search results from previous messages, if they are STRONGLY RELEVANT to the current message.

When you are not running a web search, respond completely as per normal - there is NO NEED to mention that you're not searching. 
Remember that you MUST NOT make up any false information.
Assistant: Understood. I will strictly follow these instructions in this conversation.
User: I've been using a backpack to progressively overload pullups by adding books into the backpack. The backpack is now full and there is no more space for books, what can I do?
Assistant: You could consider several options to continue increasing the weight for your pull-ups:

1. **Weighted Plates**: Purchase a weight plate or plates that you can securely attach to your backpack using straps or a belt.
2. **Weight Vest**: Invest in a weighted vest specifically designed for adding weight to bodyweight exercises like pull-ups.
3. **Resistance Bands**: Use resistance bands to provide additional resistance while performing pull-ups. They can be attached to the bar and looped around your feet or knees.
4. **Chain Weights**: Chains can be draped over your shoulders or attached to your backpack for added weight.
5. **Upgrade the Backpack**: Consider getting a larger or sturdier backpack designed for weight training that can hold more items securely.

These methods can help you continue to add weight effectively to your pull-up routine.
User: is there something that is heavier and more dense that I can fit in the backpack other than books
Assistant: