There is a room in which n lamps are placed in a row. At first, they are all off. In the first round, you turn on all the lamps. Then in the second round, you turn off every second lamp. In the third round, you toggle every 3rd lamp (if it is off, you turn it on, or if it is on, you turn it off).  For the kth round, you toggle every kth lamp. For the nth round, you toggle only the last lamp. Return the number of lamps that are on after n rounds. Input will be the number of rounds and output will be the number of lamps that are ON. Avoid using the following keywords: number, on, room, row
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