import java.io.IOException;

public class Main {
    public static void main(String[] args) throws IOException {

        StringBuilder builder = new StringBuilder();
        int buf;
        while ((buf = System.in.read()) != '\n') {
            builder.appendCodePoint(buf);
        }

        int num = Integer.parseInt(builder.toString()) % 1000;
        if (num > 0) System.out.print(1000 - num);
        else System.out.print(0);
    }
}

/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