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.*;

class Main {

	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int X = sc.nextInt();
		List<Integer> dp = new ArrayList<Integer>();
		dp.add(2);
		int i = 2;
		do {		
			boolean f = true;
			for(int j=0;j<dp.size();j++) {
				if(i%dp.get(j)==0) {
					f=false;
					break;
				}
			}
			if(f) dp.add(i);
			i++;
		} while (i<X);
		int ans = 0;
		for(i=X;i<2*X;i++) {
			boolean f=true;
			for(int j=0;j<dp.size();j++){
				if(i%dp.get(j)==0) {
					f=false;
					break;
				}
			}
			if(f) {
				ans=i;
				break;
			}
		}
		System.out.println(X==2?2:ans);
	}
}