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 Fortran (gfortran v4.8.4) (judge verdict: Wrong Answer)

program example
	implicit none
    
    integer(8) :: X,i
    
    read(*,*) X
    
    do i=X,10**5
    
    	if(i==2 .or. i==3) then
    		write(*,*) i
            exit
        else
			if(mod(i,2)/=0 .and. mod(i,3)/=0) then
        		write(*,*) i
                exit
        	end if
        end if
        
    end do
    
end program example