#define ulli unsigned long long int
#include <iostream>
#include <algorithm>
using namespace std;

ulli GCD(ulli a, ulli b){
    ulli d = 1;
	while(a%2 == 0 &&  b%2 == 0){
        a /= 2;
        b /= 2;
        d*=2;
	}
	while(a != b){
        if(a%2 == 0) a /= 2;
        else if(b%2 == 0) b /= 2;
        else if(a > b) a = (a - b)/2;
        else b = (b - a)/2;
	}
	d*=a;
	return d;
}

ulli LCM(ulli a, ulli b){
	ulli x = a*b;
	ulli y = GCD(a, b);
	x /= y;
	return x;
}


int main(){
	ulli a, b, min, imin,x;
	cin>>a>>b;

	imin = -1;
	min = 9999999999999999999;

	for(ulli N = 1; N < 300000; N++){
		x = LCM(a+N, b+N);
		if(x < min){
			min = x;
			imin = N;
		}
/*		if(x == max(a+N, b+N)){
			break;
		}*/
	}
	cout<<imin;
	return 0;
}