#include<stdio.h>
#include<string>
#include <stdlib.h>
#include<iostream>
#include<string.h>
#include<algorithm>
#include<math.h>
using namespace std;

int main() {
	int n;
	cin >> n;
	if (n == 1) n++;
	for (int i = n; i <= 10000000; i++) {
		int flag = 0;
		for (int j = 2; j <= sqrt(i); j++)
		{
			if ((i%j) == 0)
			{
				flag = 1;
				break;
			}
		}
		if (flag == 0)
		{
			cout << i;
			break;
		}
	}
	return 0;
}