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.Scanner;

public class Main {
	public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long X = sc.nextLong();
        //素数を真偽判定する
        boolean result;

        for(long i = X; i < 100010 ; i++){
            //素数であると仮定して初期化
            result = true;
            for(long j = 2; j < i; j++){
                if(i % j == 0){
                    //約数を持つ場合素数でない
                    result = false;
                    sc.close();
                    break;
                }
            }
            //結果が真であるなら素数としてカウント
            if(result && i >= X){
            	sc.close();
            	System.out.println(i);
            	break;
            }
        }
    }
}