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;
	int a;
	scanf("%d", &x);
	a = x;
	if (x >= 8) {
		for (int i = 0; i < 10000-a; i++) {

			x++;
			if ((x % 2 != 0) && (x % 3 != 0) && (x % 5 != 0) && (x % 7 != 0)) {
				printf("%d\n", x);
				break;
			}
		}
	}
	else {
		if ((x == 2) || (x == 3) || (x == 5) || (x == 7))
			printf("%d\n", x);
		else if ((x == 4) || (x == 6))
			printf("%d\n", x + 1);
	}
	return 0;
}