#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

ll a,b,d;

ll bestn=-1;
ll bestlcm = -1;
ll beste;

inline ll gcd(ll a, ll b) {
  if (!b) return a;
  return gcd(b, a%b);
}

void go(int e) {
  ll n = e-b%e;
  ll x = b + n;
  ll y = a + n;
  ll lcm = x/gcd(x,y)*y;
  if (bestlcm==-1 || lcm<bestlcm || (lcm==bestlcm && n < bestn)) {
	bestn=n;
	bestlcm=lcm;
	beste=e;
  }
}

int main (){

  cin>>a>>b;
  if (a>b) swap(a,b);

  d = b-a;
  if (d==0) {
	cout<<1<<endl; return 0;
  }
  //cerr<<"d="<<d<<endl;

  for (ll f=1;f*f<=d;f++) {
	if (d%f) continue;

	ll e= d/f;

	go(e);
	go(f);
  }

  //cerr<<"bestn = "<<bestn<<endl;
  //cerr<<"bestlcm = "<<bestlcm<<endl;
  //cerr<<"beste = "<<beste<<endl;

  cout<<bestn<<endl;

  return 0;
}