In a room, there are 2019 aligned switches, each connected to a light bulb. Initially, all the light bulbs are switched on. Then, 2019 people enter the room one by one and perform the following operation: 

- The first person toggles every switch.
- The second person toggles every second switch.
- The third person toggles every third switch.
- This continues until the 2019th person toggles every 2019th switch.

Determine how many light bulbs remain switched on after all 2019 people have entered the room and completed their operations.

Let's think step by step and output the final answer within \boxed{}.
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