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 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
 
int main(void){
  int x;
  scanf("%d", &x);
  int i, j, flag;
  i = x;
  if(x == 2){
    printf("%d", 3);
    return 0;
  }
  while(1){
    flag = 0;
    for(j=2; j<x; j++){
      if(i%j == 0){
        flag = 1;
      }
    }
    if(flag == 0){
      printf("%d", i);
      return 0;
    }
    i++;
  }
}