import java.util.Scanner;

public class Main {
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        final int N = sc.nextInt();
        
        System.out.println(N % 1000 == 0 ? 0 : 1000 - N % 1000);
    }
} import java.util.Scanner; Scanner java.util public class Main {
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        final int N = sc.nextInt();
        
        System.out.println(N % 1000 == 0 ? 0 : 1000 - N % 1000);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        final int N = sc.nextInt();
        
        System.out.println(N % 1000 == 0 ? 0 : 1000 - N % 1000);
    } main {
        Scanner sc = new Scanner(System.in);
        
        final int N = sc.nextInt();
        
        System.out.println(N % 1000 == 0 ? 0 : 1000 - N % 1000);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) final int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc System.out.println(N % 1000 == 0 ? 0 : 1000 - N % 1000) System.out.println System.out System System.out N % 1000 == 0 ? 0 : 1000 - N % 1000 N % 1000 == 0 N % 1000 N 1000 0 0 1000 - N % 1000 1000 N % 1000 N 1000 String[] args args public class Main {
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        final int N = sc.nextInt();
        
        System.out.println(N % 1000 == 0 ? 0 : 1000 - N % 1000);
    }
} public class Main {
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        final int N = sc.nextInt();
        
        System.out.println(N % 1000 == 0 ? 0 : 1000 - N % 1000);
    }
} Main
import java.util.Scanner;

public class Main {
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        
        final int N = sc.nextInt();
        
        System.out.println(N % 1000 == 0 ? 0 : 1000 - N % 1000);
    }
}
