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

class Main {
	
	public static void out (Object o) {
		System.out.println(o);
	}
	
	public static int solve (int n) {
		if (n % 2 == 0) return n / 2;
		for (int i = 3; i * i <= n; i += 2)
			if (n % i == 0) return n / i;
		return 1;
	}
	
	public static void main (String[] args) throws IOException {
		BufferedReader br = 
			new BufferedReader(new InputStreamReader(System.in));
		
		String[] line = br.readLine().split(" ");
		
		out(solve(Integer.parseInt(line[0])));
	}
}