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 Julia (0.5.0) (judge verdict: Accepted)

function check(n)
  
  for i in 2:round(Int,sqrt(n))
    
    if n % i == 0
      return false
    end
    
  end
  
  return true
  
end

function main()
  
  X = parse(Int, readline())
  
  prime = false
  
  while prime == false
    
	prime = check(X)
    X += 1
    
  end
	
  println(X-1)
  
end

main()