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 Scala (2.11.7) (judge verdict: Accepted)

import java.util.Scanner

object Main extends App {

  val sc = new Scanner(System.in)

  val x = sc.nextInt


  val res = (x to x + 1000).find(isPrime).get

  println(res)

  def isPrime(num: Int): Boolean = {
    num match {
      case 1 => false
      case 2 => true
      case x => (2 to Math.sqrt(x).toInt).forall(num % _ != 0 )
    }
  }
}