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() {
	int N;
	scanf("%d",&N);
	if (N % 2 == 0) {
		N++;
	}
	for (int i = N;i<2*N; i = i + 2) {
		for (int j = 3; j <= i/2; j = j + 2) {
			if (i % j == 0) {
				goto AC;
			}
		}
		printf("%d",i);
		break;
		AC:printf("");
	}
	return 0;
}