Problem Statement

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

Input

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

Output

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

Constraints

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

Sample Input 1

20

Sample Output 1

23

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

Sample Input 2

2

Sample Output 2

2

X itself can be a prime number.

Sample Input 3

99992

Sample Output 3

100003

见题面 Input 部分

见题面 Output 部分