#include <iostream>

using namespace std;

template <class T>
void _swap(T& a, T& b) {
	T c(a);
	a=b;b=c;
}

int main()
{
	long long a, b;
	cin >> a >> b;
	if (a > b) _swap(a, b);
	for (long long i = 1; i < b-a; i++)
		if ((b+i)%(a+i) == 0) {
			cout << i << endl;
			return 0;
		}
	cout << 1 << endl;
	return 0;
}