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 Kotlin (1.0.0) (judge verdict: Accepted)

import java.io.BufferedReader
import java.io.IOException
import java.io.InputStreamReader
import java.io.PrintWriter
import java.util.*

/**
 * @author: pashka
 */

fun prime(x: Int) : Boolean {
    for (i in 2 until x) {
        if (x % i == 0) return false
    }
    return true
}

private fun solve() {
    var x = nextInt()
    while (!prime(x)) {
        x++
    }
    println(x)
}

fun main(args: Array<String>) {
    solve()
    out.close()
}

private var br = BufferedReader(InputStreamReader(System.`in`))
private var st: StringTokenizer? = null
private var out = PrintWriter(System.out)

@Throws(IOException::class)
private fun next(): String {
    while (st == null || !st!!.hasMoreTokens()) {
        st = StringTokenizer(br.readLine())
    }
    return st!!.nextToken()
}

@Throws(IOException::class)
private fun nextInt(): Int {
    return next().toInt()
}

@Throws(IOException::class)
private fun nextLong(): Long {
    return next().toLong()
}