/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
	PrintWriter out = new PrintWriter(System.out);
                Scanner scanner = new Scanner(System.in);
                int N = scanner.nextInt();
                for (int d = 2; d < N / d; d++) {
                        if (N % d == 0) {
                                N = d;
                                break;
                        }
                }
                out.print(N);
                out.flush();
	}
}

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OQ==

9