import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
class Main{
  public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(br.readLine());
    while(n > 0){
      n -= 1000;
    }
    System.out.println(-n);
  }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io class Main{
  public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(br.readLine());
    while(n > 0){
      n -= 1000;
    }
    System.out.println(-n);
  }
} Main public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(br.readLine());
    while(n > 0){
      n -= 1000;
    }
    System.out.println(-n);
  } main {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(br.readLine());
    while(n > 0){
      n -= 1000;
    }
    System.out.println(-n);
  } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) int n = Integer.parseInt(br.readLine()); n Integer.parseInt(br.readLine()) Integer.parseInt Integer br.readLine() br.readLine br while(n > 0){
      n -= 1000;
    } n > 0 n 0 {
      n -= 1000;
    } n -= 1000 n 1000 System.out.println(-n) System.out.println System.out System System.out -n n String[] args args
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
class Main{
  public static void main(String[] args) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(br.readLine());
    while(n > 0){
      n -= 1000;
    }
    System.out.println(-n);
  }
}
