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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());

        final int mx = 1100001;
        int hurui[] = new int[mx];

        for (int i = 2;i < Math.sqrt(mx);i++) {
            int ni = i;
            ni += i;
            while(ni < mx) {
                hurui[ni]++;
                ni+=i;
            }
        }

        for(int i=n;i<mx;i++) {
            if(hurui[i] == 0) {
                System.out.print(i);
                break;
            };
        }

    }
}