/*
 * main.cpp
 *
 *  Created on: 2016 febr. 11
 *      Author: magistvan
 */

#include <iostream>
using namespace std;

int main() {
	int lcm, a, b, n = 1, sol = 1;
	cin >> a >> b;
	++a;
	++b;
	lcm = a * b;
	while ((a < lcm) && (b < lcm)) {
		int temp = 0;
		for (int i = a; i <= a * b; ++i) {
			if ((i % a == 0) && (i % b == 0)) {
				temp = i;
				break;
			}
		}
		if (temp < lcm) {
			lcm = temp;
			sol = n;
		}
		++n;
		++a;
		++b;
	}
	cout << sol;
	return 0;
}