import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.time.LocalTime;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;


public class Main {

    public static void main(String[] args) {
    
    	FastScanner scan = new FastScanner();
    	
    	int n = scan.nextInt();
    	System.out.println((-n%1000 + 1000) % 1000);
    	}   
    
    
    static class FastScanner{
    	
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	StringTokenizer st = new StringTokenizer("");
    	String next() {
    		while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			}
    		return st.nextToken();
    	}
    	
    	int nextInt() {
    		return Integer.parseInt(next());
    	}
    	
    	int [] readArray(int n) {
    		int [] a = new int[n];
    		for(int i=0; i<n ; i++) a[i] = nextInt();
    		return a;
    	}
    	
    	long nextLong() {
    		return Long.parseLong(next());
    	}
    	
    	
    }
    
   
}
 import java.io.*; io.* java import java.math.*; math.* java import java.security.*; security.* java import java.text.*; text.* java import java.time.LocalTime; LocalTime java.time import java.util.*; util.* java import java.util.concurrent.*; concurrent.* java.util import java.util.regex.*; regex.* java.util public class Main {

    public static void main(String[] args) {
    
    	FastScanner scan = new FastScanner();
    	
    	int n = scan.nextInt();
    	System.out.println((-n%1000 + 1000) % 1000);
    	}   
    
    
    static class FastScanner{
    	
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	StringTokenizer st = new StringTokenizer("");
    	String next() {
    		while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			}
    		return st.nextToken();
    	}
    	
    	int nextInt() {
    		return Integer.parseInt(next());
    	}
    	
    	int [] readArray(int n) {
    		int [] a = new int[n];
    		for(int i=0; i<n ; i++) a[i] = nextInt();
    		return a;
    	}
    	
    	long nextLong() {
    		return Long.parseLong(next());
    	}
    	
    	
    }
    
   
} Main public static void main(String[] args) {
    
    	FastScanner scan = new FastScanner();
    	
    	int n = scan.nextInt();
    	System.out.println((-n%1000 + 1000) % 1000);
    	} main {
    
    	FastScanner scan = new FastScanner();
    	
    	int n = scan.nextInt();
    	System.out.println((-n%1000 + 1000) % 1000);
    	} FastScanner scan = new FastScanner(); scan new FastScanner() int n = scan.nextInt(); n scan.nextInt() scan.nextInt scan System.out.println((-n%1000 + 1000) % 1000) System.out.println System.out System System.out (-n%1000 + 1000) % 1000 (-n%1000 + 1000) -n%1000 -n n 1000 1000 1000 String[] args args static class FastScanner{
    	
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	StringTokenizer st = new StringTokenizer("");
    	String next() {
    		while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			}
    		return st.nextToken();
    	}
    	
    	int nextInt() {
    		return Integer.parseInt(next());
    	}
    	
    	int [] readArray(int n) {
    		int [] a = new int[n];
    		for(int i=0; i<n ; i++) a[i] = nextInt();
    		return a;
    	}
    	
    	long nextLong() {
    		return Long.parseLong(next());
    	}
    	
    	
    } FastScanner BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) StringTokenizer st = new StringTokenizer(""); st new StringTokenizer("") String next() {
    		while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			}
    		return st.nextToken();
    	} next {
    		while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			}
    		return st.nextToken();
    	} while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			} !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			} catch (IOException e){
    				e.printStackTrace();
    			} IOException e {
    				e.printStackTrace();
    			} e.printStackTrace() e.printStackTrace e {
    				st = new StringTokenizer(br.readLine());
    			} st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
    		return Integer.parseInt(next());
    	} nextInt {
    		return Integer.parseInt(next());
    	} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next int [] readArray(int n) {
    		int [] a = new int[n];
    		for(int i=0; i<n ; i++) a[i] = nextInt();
    		return a;
    	} readArray {
    		int [] a = new int[n];
    		for(int i=0; i<n ; i++) a[i] = nextInt();
    		return a;
    	} int [] a = new int[n]; a new int[n] n for(int i=0; i<n ; i++) a[i] = nextInt(); int i=0; int i=0; i 0 i<n i n i++ i++ i a[i] = nextInt(); a[i] = nextInt() a[i] a i nextInt() nextInt return a; a int n n long nextLong() {
    		return Long.parseLong(next());
    	} nextLong {
    		return Long.parseLong(next());
    	} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {

    public static void main(String[] args) {
    
    	FastScanner scan = new FastScanner();
    	
    	int n = scan.nextInt();
    	System.out.println((-n%1000 + 1000) % 1000);
    	}   
    
    
    static class FastScanner{
    	
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	StringTokenizer st = new StringTokenizer("");
    	String next() {
    		while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			}
    		return st.nextToken();
    	}
    	
    	int nextInt() {
    		return Integer.parseInt(next());
    	}
    	
    	int [] readArray(int n) {
    		int [] a = new int[n];
    		for(int i=0; i<n ; i++) a[i] = nextInt();
    		return a;
    	}
    	
    	long nextLong() {
    		return Long.parseLong(next());
    	}
    	
    	
    }
    
   
} public class Main {

    public static void main(String[] args) {
    
    	FastScanner scan = new FastScanner();
    	
    	int n = scan.nextInt();
    	System.out.println((-n%1000 + 1000) % 1000);
    	}   
    
    
    static class FastScanner{
    	
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	StringTokenizer st = new StringTokenizer("");
    	String next() {
    		while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			}
    		return st.nextToken();
    	}
    	
    	int nextInt() {
    		return Integer.parseInt(next());
    	}
    	
    	int [] readArray(int n) {
    		int [] a = new int[n];
    		for(int i=0; i<n ; i++) a[i] = nextInt();
    		return a;
    	}
    	
    	long nextLong() {
    		return Long.parseLong(next());
    	}
    	
    	
    }
    
   
} Main
import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.time.LocalTime;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;


public class Main {

    public static void main(String[] args) {
    
    	FastScanner scan = new FastScanner();
    	
    	int n = scan.nextInt();
    	System.out.println((-n%1000 + 1000) % 1000);
    	}   
    
    
    static class FastScanner{
    	
    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    	StringTokenizer st = new StringTokenizer("");
    	String next() {
    		while(!st.hasMoreTokens())
    			try {
    				st = new StringTokenizer(br.readLine());
    			} catch (IOException e){
    				e.printStackTrace();
    			}
    		return st.nextToken();
    	}
    	
    	int nextInt() {
    		return Integer.parseInt(next());
    	}
    	
    	int [] readArray(int n) {
    		int [] a = new int[n];
    		for(int i=0; i<n ; i++) a[i] = nextInt();
    		return a;
    	}
    	
    	long nextLong() {
    		return Long.parseLong(next());
    	}
    	
    	
    }
    
   
}

