BiggestPrimeNumber

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int N = Integer.parseInt(scan.nextLine());
        int[] numbers = new int[N];
        int max = Integer.MIN_VALUE;
        int numb ;
        for( int i = numbers.length ; i >=2 ;i--){
            boolean prime = true;
            int divider = 2;
            int maxDivider = (int) Math.sqrt(i);
            while (divider <= maxDivider) {
                if (i % divider == 0) {
                    prime = false;
                    break;
                }
                divider++;
            }
            if (prime) {
                numb = i;
                if(max>numb){
                    System.out.println(max);
                    break;
                }
                if(numb>max){
                    max=numb;
                    numb=0;
                }
            }

        }

    }
}