import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        try(Scanner sc = new Scanner(System.in);){
            System.out.println(new Main().run(sc));
        }
    }
    
    private String run(Scanner sc){
        int n = Integer.parseInt(sc.next());
        while(n > 0){
            n -= 1000;
        }
        return Integer.toString(Math.abs(n));
    }
    
}

/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