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: Wrong Answer)

/*   BismillahHir Rahmanir Rahim   */
/*  Author: Sorowar Mahabub, 01521-564157  */

#include <stdio.h>

int isPrime(int n) {
    int j, flag = 1;
    for (j = 2; j*j <= n / 2; ++j) {
        if (n % j == 0) {
            flag = 0;
            break;
        }
    }
    return flag;
}

int main() {
    int end, i, flag;
    scanf("%d",  &end);

    for (i = 2; ; ++i) {
        flag= isPrime(i);
        if (flag == 1) {
            if(i>=end) {
                printf("%d\n", i);
                break;
            }
        }
    }
    return 0;
}