What is a one-sentence summary of the following article?
Tap the Instagram app icon, which resembles a multicolored camera front. This will open your Instagram feed if you're logged into your account. If you aren't logged into Instagram, tap the Log in link if necessary, then enter your username/email address/phone number and password. It's in the bottom-right corner of the screen. You'll find this tab at the top of the screen. It will have the number of current followers above it. For example, if you have 100 followers, you'd tap 100 followers here. Scroll through your list of followers and look for missing names. If you don't see a particular person whom you know was following you, they unfollowed you.  This is difficult to manage if you recently lost a large number of followers, but you should be able to get an idea of the people who stopped following you if they're people you also follow or interact with. The user in question may have deleted their Instagram account instead. You can check to see whether or not they still have an account by tapping the magnifying glass icon at the bottom of the screen and then searching for their name.

Summary:
Open Instagram. Tap the "Profile"  icon. Tap followers. Look for absent followers.