Compounds that have the same molecular formula but different chemical structures are called isomers. Depending on what types of differences there are between the structures, it is possible to classify isomers into various sub-types.
The Limit. You can follow up to 7,500 users before receiving the aforementioned error. Instagram invoked this limit to reduce spam in their system and keep users in compliance of their Community Guidelines. However, some users can follow more than 7,500 users if they did so before Instagram imposed the limit. Some Instagram users also claim there's an hourly or daily limit to the number of new followers you can acquire, but Instagram has not confirmed such restrictions.
If you have too many hashtags, your followers will feel like your images are too spammy. Hide away the hashtags by using them withing the caption sentence e.g. I really #love this #girl or place them right at the bottom of the caption. Instagram will limit you to a maximum of 30 hashtags per post.