#include <iostream>

using namespace std;

int input ();
int difference (int, int);
int calculateWrongAns (int);

int main()
{
    int num1;
    int num2;
    num1 = input();
    num2 = input();

    int actualAns = difference(num1, num2);
    int res = calculateWrongAns(actualAns);
    cout << res;
    return 0;
}

int input () {
    int x;
    cin >> x;
    return x;
}

int difference (int x, int y) {
    if (x > y) {
        return x - y;
    } else if (x < y) {
        return y - x;
    } else {
        return 0;
    }
}

int calculateWrongAns (int actualAns) {
    int lastNumber = actualAns % 10;
    int otherNumbers = actualAns / 10;
    int res;
    if (otherNumbers != 0) {
        res = (otherNumbers * 10) + (lastNumber == 1 ? 2 : lastNumber -     1);
    } else {
        res = lastNumber == 1 ? 2 : lastNumber - 1;
    }

    return res;
}