class Main{
	
public static void main (String[] args) {
	
	java.util.Scanner sc = new java.util.Scanner(System.in);
	
	int N = sc.nextInt();
	boolean flag = true;
	
	while (flag) {
		N-=1000;
		if (N<=0) {
			flag=false;
			N*=-1;
		}
	}
	
	System.out.println(N);
	
	sc.close();;
	
}
	
	
}


/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