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.ArrayList;
import java.util.Scanner;

public class Main {
	public static boolean ch(ArrayList<Integer> l,int num) {
		boolean flag = true;
		for(int i = 0; i < l.size();i++) {
			if(num%l.get(i)==0) {
				flag = false;
				break;
			}
		}
		return flag;
	}
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<Integer> intList = new ArrayList<Integer>();
		intList.add(2);
		int ans = 3;
		if(N==2) {
			System.out.println(2);
		}else {
			while(true) {
				boolean d = ch(intList,ans);
				if(d == true) {
					if(ans>=N) {
						System.out.println(ans);
						break;
					}else {
						intList.add(ans);
					}
				}
              ans = ans + 2;
			}
		}


	}

}