import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
 
public class Main {
	public static void main(String[] args) throws NumberFormatException,
	IOException {Solve solve = new Solve();solve.solve();}
}
class Solve{
	void solve() throws NumberFormatException, IOException{
		ContestScanner in = new ContestScanner();
		Writer out = new Writer();
		long n = in.nextLong();
		long nt = n;
		List<Long> list = new ArrayList<>();
		for(long i=2; i*i<=n; i++){
			if(nt%i==0){
				list.add(i);
				while(nt%i==0) nt /= i;
			}
		}
		list.add(nt);
		Collections.sort(list);
		for(int i=0; i<list.size(); i++){
			if(list.get(i)>2){
				System.out.println(list.get(i));
				return;
			}
		}
	}
}
 
class MultiSet<T> extends HashMap<T, Integer>{
	@Override
	public Integer get(Object key){return containsKey(key)?super.get(key):0;}
	public void add(T key,int v){put(key,get(key)+v);}
	public void add(T key){put(key,get(key)+1);}
}
class Timer{
	long time;
	public void set(){time = System.currentTimeMillis();}
	public long stop(){return System.currentTimeMillis()-time;}
}
class Writer extends PrintWriter{
	public Writer(String filename) throws IOException
	{super(new BufferedWriter(new FileWriter(filename)));}
	public Writer() throws IOException{super(System.out);}
}
class ContestScanner {
	private BufferedReader reader;
	private String[] line;
	private int idx;
	public ContestScanner() throws FileNotFoundException 
	{reader = new BufferedReader(new InputStreamReader(System.in));}
	public ContestScanner(String filename) throws FileNotFoundException
	{reader = new BufferedReader(new InputStreamReader(new FileInputStream(filename)));}
	public String nextToken() throws IOException {
		if (line == null || line.length <= idx) {
			line = reader.readLine().trim().split(" ");
			idx = 0;
		}
		return line[idx++];
	}
	public String readLine() throws IOException{return reader.readLine();}
	public long nextLong() throws IOException, NumberFormatException
	{return Long.parseLong(nextToken());}
	public int nextInt() throws NumberFormatException, IOException
	{return (int) nextLong();}
	public double nextDouble() throws NumberFormatException, IOException 
	{return Double.parseDouble(nextToken());}
}