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 Perl (v5.18.2) (judge verdict: Accepted)

sub Check_Prime_number{
    my $number = shift;
    if($number == 2){ return 1;}
    for ( my $i=2;$i*$i<$number;$i++){
        if($number % $i ==0){
            return 0;
        }
    }
    return 1;
}
 
my $x = <STDIN>;chomp $x;
my $i =0;
my $ans =0;
while(1){
    if(&Check_Prime_number($x+$i) == 1){
        $ans=$x+$i;
        last;
    } else{
        $i+=1;
    }
}
 
print("$ans\n");