#include<stdio.h>
#include<iostream>
using namespace std;


#pragma warning(push)
#pragma warning(disable: 4996)

long long a, b;
long long increment;

int main()
{
	//freopen("lcm.in", "r", stdin);
	//freopen("lcm.out", "w", stdout);

	cin >> a >> b;
	
	if (a < b)
	{
		long long x = a; 
		a = b;
		b = x;
	}
	
	long long nr_a_initial = a;

	while (a % b != 0)
	{
		a++;
		b++;
	}

	cout << a - nr_a_initial << endl;
}


#pragma warning(pop)