import java.util.*;
import java.io.*;

public class Exercise75{
  public static void main (String[] args) throws IOException{

    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String nStr = new String(in.readLine());

    long nd = Long.parseLong(nStr);
    long n = nd;

    long[] factor = new long[20];
    int count = 0;



    for (long i = 3; i * i <= n; i ++){
      if(n % i == 0){
        while (n % i == 0){
          factor[count] = i;
          n /= i;
        }
        count++;
      }
    }

    if (factor[0] > 2){
      System.out.println(factor[0]);
    }else{
      if(n % 2 == 0 && n / 2 != 2){
        System.out.println(n / 2);
      }else{
        System.out.println(n);
      }
    }
  }
}