        import java.util.Scanner;
         
        public class Main {
         
        	public static void main(String[] args) {
                Scanner scan = new Scanner(System.in);
                String price = scan.nextLine();
                scan.close();
         
                int otsuri = Integer.parseInt(price) % 1000;
                if (otsuri == 0) {
                    System.out.println(otsuri);
                } else {
                    System.out.println(1000 - otsuri);
                }
            }
        }
/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