#include<iostream>

#include<cstdio>

#include<vector>

#include<cstring>

using namespace std;

typedef long long ll;

const int mod=1e9+;

ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}

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

const int maxn=2e5+;

vector<ll> yinzi;

int main(){

    ll a,b;

    cin>>a>>b;

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

    if(a==b||b%a==||b-a==){

        cout<<<<endl;

        return ;

    }

    int cha=b-a;

    for(int i=;i*i<=cha;i++){  //计算b-a的所有因子

        if(cha%i==){

            yinzi.push_back(i);

            if(i*i!=cha) yinzi.push_back(cha/i);

        }

    }

    ll ans=lcm(a,b),x=;

    for(int i=;i<yinzi.size();i++){

        int k=;

        if(a%yinzi[i]) k=yinzi[i]-a%yinzi[i];

        if(k>=){

            ll tmp=(a+k)/yinzi[i]*(b+k);

            if(tmp==ans&&k<x) x=k;

            if(tmp<ans){

                ans=tmp;

                x=k;

            }

        }

    }

    cout<<x<<endl;

    return ;

}