Problem:
Score: 300 points

Problem Statement

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 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

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.math.*;
class Main {
  public static void main(String[] args) {
    Scanner in=new Scanner(System.in);
    int n=in.nextInt();
    BigInteger bi1, bi2, bi3;
    bi1 = new BigInteger(Integer.toString(n));


    if(bi1.isProbablePrime(1))
    System.out.println(n);
    else{
    bi2 = bi1.nextProbablePrime();
    System.out.println(bi2);
    }
  }
}