import java.util.*;


public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int x = sc.nextInt();
        int ans=0;
        
        for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        }
        
        for(int i=0; x>4; i++){
            x=x-5;
            ans+=5;
        }
        
        System.out.println(ans);
	}
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int x = sc.nextInt();
        int ans=0;
        
        for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        }
        
        for(int i=0; x>4; i++){
            x=x-5;
            ans+=5;
        }
        
        System.out.println(ans);
	}
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int x = sc.nextInt();
        int ans=0;
        
        for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        }
        
        for(int i=0; x>4; i++){
            x=x-5;
            ans+=5;
        }
        
        System.out.println(ans);
	} main {
        Scanner sc = new Scanner(System.in);
        
        int x = sc.nextInt();
        int ans=0;
        
        for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        }
        
        for(int i=0; x>4; i++){
            x=x-5;
            ans+=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 int ans=0; ans 0 for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        } int i=0; int i=0; i 0 x>499 x 499 i++ i++ i {
            x=x-500;
            ans+=1000;
        } {
            x=x-500;
            ans+=1000;
        } x=x-500 x x-500 x 500 ans+=1000 ans 1000 for(int i=0; x>4; i++){
            x=x-5;
            ans+=5;
        } int i=0; int i=0; i 0 x>4 x 4 i++ i++ i {
            x=x-5;
            ans+=5;
        } {
            x=x-5;
            ans+=5;
        } x=x-5 x x-5 x 5 ans+=5 ans 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) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int x = sc.nextInt();
        int ans=0;
        
        for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        }
        
        for(int i=0; x>4; i++){
            x=x-5;
            ans+=5;
        }
        
        System.out.println(ans);
	}
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int x = sc.nextInt();
        int ans=0;
        
        for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        }
        
        for(int i=0; x>4; i++){
            x=x-5;
            ans+=5;
        }
        
        System.out.println(ans);
	}
} Main
import java.util.*;


public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int x = sc.nextInt();
        int ans=0;
        
        for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        }
        
        for(int i=0; x>4; i++){
            x=x-5;
            ans+=5;
        }
        
        System.out.println(ans);
	}
}