#include <iostream>

using namespace std;

int main() {
	unsigned int i, N, k, j;
	cin >> N;
	for (i = N; true; ++i) {
		k = 0;
		for (j = 3; j < i; ++j) {
			if (i % j == 0)  k++;
		}
		if (k == 0) {
			cout << i;
			return 0;
		}
	}
	return 0;
}