import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

      	int th = x/500;
      	int g = (x - (th*500))/5;

		int ans =(th*1000)+(g*5);

		System.out.println(ans);

		sc.close();
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

      	int th = x/500;
      	int g = (x - (th*500))/5;

		int ans =(th*1000)+(g*5);

		System.out.println(ans);

		sc.close();
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

      	int th = x/500;
      	int g = (x - (th*500))/5;

		int ans =(th*1000)+(g*5);

		System.out.println(ans);

		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

      	int th = x/500;
      	int g = (x - (th*500))/5;

		int ans =(th*1000)+(g*5);

		System.out.println(ans);

		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int x = sc.nextInt(); x sc.nextInt() sc.nextInt sc int th = x/500; th x/500 x 500 int g = (x - (th*500))/5; g (x - (th*500))/5 (x - (th*500)) x (th*500) th 500 5 int ans =(th*1000)+(g*5); ans (th*1000)+(g*5) (th*1000) th 1000 (g*5) g 5 System.out.println(ans) System.out.println System.out System System.out ans sc.close() sc.close sc String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

      	int th = x/500;
      	int g = (x - (th*500))/5;

		int ans =(th*1000)+(g*5);

		System.out.println(ans);

		sc.close();
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

      	int th = x/500;
      	int g = (x - (th*500))/5;

		int ans =(th*1000)+(g*5);

		System.out.println(ans);

		sc.close();
	}
} Main
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

      	int th = x/500;
      	int g = (x - (th*500))/5;

		int ans =(th*1000)+(g*5);

		System.out.println(ans);

		sc.close();
	}
}