Find the minimum prime number greater than or equal to X.

-----Notes-----
A prime number is an integer greater than 1 that cannot be evenly divided by any positive integer except 1 and itself.
For example, 2, 3, and 5 are prime numbers, while 4 and 6 are not.

-----Constraints-----
- $2 \le X \le 10^5$
- All values in input are integers.

-----Input-----
Input is given from Standard Input in the following format:
X

-----Output-----
Print the minimum prime number greater than or equal to X.

-----Sample Input-----
20

-----Sample Output-----
23

The minimum prime number greater than or equal to 20 is 23.

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