import java.util.*;
import java.text.*;
class Different {
    public static void main(String[] args) {
        DecimalFormat df = new DecimalFormat("#,#########");
        Scanner in = new Scanner(System.in);
            while(in.hasNext()) {
            double a = in.nextDouble();
            double b = in.nextDouble();

            double answer = (Math.abs(a - b));
            df.format(answer);
            System.out.println(answer);
            }
            in.close();
        }
    }