import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        try{
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            
            int N = Integer.parseInt(br.readLine());
            
            while(true){
                N = N - 1000;
                
                if(N <= 0){
                    break;
                }
            }
            
            System.out.println(Math.abs(N));
            
        }catch(Exception e){
            System.out.println(e);
        }
    }
}
/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