import java.util.*;
class Main
{
    public static void main(String args[]) {
        Scanner sc=new Scanner(System.in);
        long x=sc.nextLong();
        long ans=0;
        while(x>4) {
            if (x / 500 > 0) {
                ans += 1000;
                x -= 500;
                continue;
            }
            if (x / 5> 0) {
                ans += 5;
                x -= 5;
                continue;
            }
        }
        System.out.println(ans);
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz