import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int res = 0;
		res += X / 500 * 1000;
		X %= 500;
		res += X / 5 * 5;
		System.out.println(res);
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int res = 0;
		res += X / 500 * 1000;
		X %= 500;
		res += X / 5 * 5;
		System.out.println(res);
	}
} Main public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int res = 0;
		res += X / 500 * 1000;
		X %= 500;
		res += X / 5 * 5;
		System.out.println(res);
	} main {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int res = 0;
		res += X / 500 * 1000;
		X %= 500;
		res += X / 5 * 5;
		System.out.println(res);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int X = sc.nextInt(); X sc.nextInt() sc.nextInt sc int res = 0; res 0 res += X / 500 * 1000 res X / 500 * 1000 X / 500 X 500 1000 X %= 500 X 500 res += X / 5 * 5 res X / 5 * 5 X / 5 X 5 5 System.out.println(res) System.out.println System.out System System.out res String[] args args public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int res = 0;
		res += X / 500 * 1000;
		X %= 500;
		res += X / 5 * 5;
		System.out.println(res);
	}
} public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int res = 0;
		res += X / 500 * 1000;
		X %= 500;
		res += X / 5 * 5;
		System.out.println(res);
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int res = 0;
		res += X / 500 * 1000;
		X %= 500;
		res += X / 5 * 5;
		System.out.println(res);
	}
}
