#include <iostream>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int gcd(int a, int b){
	if(b==0){
		return a;
	}
	else {
		int r = a % b;
		return gcd(b,r);
	}
	
}

int lcm(int a, int b){
	return (a*b)/gcd(a,b);
}


int main() {
	
	
	int a,b;
	cin>>a;
	cin>>b;
	int currentLcm, minLcm, startingLcm = lcm(a,b);
	minLcm = currentLcm = startingLcm;
	int iii=0;
	for(; /*currentLcm > max(a,b) + iii &&*/ minLcm > max(a,b) + iii; iii++){
		currentLcm = lcm(a+iii,b+iii);

		if(currentLcm<minLcm){
			minLcm = currentLcm;
		}
	}
	cout<<iii-1;
	
	return 0;
}