import java.util.*;

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

        long ans = 0;
        ans += (x / 500) * 1000;
        x -= (x / 500) * 500;
        ans += (x / 5) * 5;

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

        long ans = 0;
        ans += (x / 500) * 1000;
        x -= (x / 500) * 500;
        ans += (x / 5) * 5;

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

        long ans = 0;
        ans += (x / 500) * 1000;
        x -= (x / 500) * 500;
        ans += (x / 5) * 5;

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

        long ans = 0;
        ans += (x / 500) * 1000;
        x -= (x / 500) * 500;
        ans += (x / 5) * 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 long ans = 0; ans 0 ans += (x / 500) * 1000 ans (x / 500) * 1000 (x / 500) x 500 1000 x -= (x / 500) * 500 x (x / 500) * 500 (x / 500) x 500 500 ans += (x / 5) * 5 ans (x / 5) * 5 (x / 5) x 5 5 System.out.println(ans) System.out.println System.out System System.out ans String[] args args
import java.util.*;

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

        long ans = 0;
        ans += (x / 500) * 1000;
        x -= (x / 500) * 500;
        ans += (x / 5) * 5;

        System.out.println(ans);
    }
}