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 scala.util.control.Breaks

object Main extends App {
  def isPrime(n: Int): Boolean = {
    if (n < 2 || (n > 2 && n % 2 == 0)) {
      return false
    } else if (n == 2) {
      return true
    }
    for (i <- 3 to Math.sqrt(n).toInt by 2 ) {
      if (n % i == 0) {
        return false
      }
    }
    return true
  }

  var x = scala.io.StdIn.readInt()
  val b = new Breaks
  b.breakable {
    while(true) {
      if(isPrime(x)) {
        b.break()
      } else {
        x = x + 1
      }
    }
  }
  println(x)
}