#include <iostream>

using namespace std;

int cmmdc(int a, int b){
	int r;
	r = a%b;
	while (r != 0){
		a = b;
		b = r;
		r = a%b;
	}
	return b;
}

int cmmmc(int a, int b){
	return (a*b) / cmmdc(a, b);
}

int main()
{
	int a, b, o, n, rez, min;
	cin >> a >> b;
	o = cmmmc(a, b);
	min = o;
	rez = 0;
	n = 1;
	while (n <= a || n <= b){
		o = cmmmc(a + n, b + n);
		if (o < min){
			min = o;
			rez = n;
			n++;
		}
		else{
			n++;
		}
	}
	cout << rez;
	return 0;
}