import java.io.PrintWriter;

import java.util.Scanner;


public class ojm1 {

    static Scanner in = new Scanner(System.in);
    static PrintWriter out = new PrintWriter(System.out, true);

    public static void main(String[] args) {

        int x = in.nextInt();
        int y = in.nextInt();
        int a;
        int s = 0;

        a = 1605 - x;

        if (a == 0) {
            s = (y - x) / 10;
            out.println(s);
        }
        if (a < 0) {
            if (a % 5 == 0) {
                s = (y - x) / 10;
            } else {
                s = (y - x) / 10 + 1;
            }
            out.println(s);
        }
        if (a > 0) {
            if (y < 1605) {
                s = 0;

            } else {
                s = (y - 1605) / 10 + 1;

            }
            out.println(s);
        }

    }
}