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 C (GCC 9.2.1) (judge verdict: Accepted)

#include <stdio.h>
#include<stdlib.h>
#define ll long long

int main(void){
  int x;
  scanf("%d",&x);
  if( x == 2 ){
    printf("%d\n",x);
    return 0;
  }

  while( 1 ){
    for(int i=2;i<x;++i){
      if( x%i == 0 ){
        ++x;
        break;
      }
      if( i == x-1 ){
        printf("%d\n",x);
        return 0;
      }
    }
  }
 
  return 0;
}