import java.util.*;

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

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