import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		long num = sc.nextLong();
		long ans = 0;

		ans += (num / 500) * 1000;
		num = num % 500;

		ans += (num / 5) * 5;
		num = num % 5;

		System.out.println(ans);

	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		long num = sc.nextLong();
		long ans = 0;

		ans += (num / 500) * 1000;
		num = num % 500;

		ans += (num / 5) * 5;
		num = num % 5;

		System.out.println(ans);

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

		long num = sc.nextLong();
		long ans = 0;

		ans += (num / 500) * 1000;
		num = num % 500;

		ans += (num / 5) * 5;
		num = num % 5;

		System.out.println(ans);

	} main {
		Scanner sc = new Scanner(System.in);

		long num = sc.nextLong();
		long ans = 0;

		ans += (num / 500) * 1000;
		num = num % 500;

		ans += (num / 5) * 5;
		num = num % 5;

		System.out.println(ans);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) long num = sc.nextLong(); num sc.nextLong() sc.nextLong sc long ans = 0; ans 0 ans += (num / 500) * 1000 ans (num / 500) * 1000 (num / 500) num 500 1000 num = num % 500 num num % 500 num 500 ans += (num / 5) * 5 ans (num / 5) * 5 (num / 5) num 5 5 num = num % 5 num num % 5 num 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);

		long num = sc.nextLong();
		long ans = 0;

		ans += (num / 500) * 1000;
		num = num % 500;

		ans += (num / 5) * 5;
		num = num % 5;

		System.out.println(ans);

	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		long num = sc.nextLong();
		long ans = 0;

		ans += (num / 500) * 1000;
		num = num % 500;

		ans += (num / 5) * 5;
		num = num % 5;

		System.out.println(ans);

	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		long num = sc.nextLong();
		long ans = 0;

		ans += (num / 500) * 1000;
		num = num % 500;

		ans += (num / 5) * 5;
		num = num % 5;

		System.out.println(ans);

	}
}