#include <iostream>

using namespace std;

bool isNeighbourNum(int n) {
	while (n != 0) {
		if (n % 10 == (n / 10) % 10)
			return false;
		n /= 10;
	}
	return true;
}

int subNeighbours(int a, int b) {
	int smallest = 0, biggest = 0;

	for (int i = a; i <= b; i++) {
		if (isNeighbourNum(i)) {
			if (i < smallest || !smallest)
				smallest = i;
			if (i > biggest || !biggest)
				biggest = i;
		}
	}

	if (!smallest || !biggest) {
		return -1;
	}

	return biggest - smallest;
}

int main() {
	cout << "a = ";
	int a;
	cin >> a;
	cout << "b = ";
	int b;
	cin >> b;

	int sub = subNeighbours(a, b);

	if (sub == -1)
		cout << "No adjacent numbers!" << endl;
	else
		cout << sub << endl;
}