某考试 T1 lcm

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<cstdlib>
#include<ctime>
#define ll long long
using namespace std;

int A,B,C,N,d[2333],num;
ll ans=1ll<<62ll,w;

//int gcd(int x,int y){ return y?gcd(y,x%y):x;}

inline void solve(){
	C=A-B;
	for(int i=1;i*(ll)i<=C;i++) if(!(C%i)){
		d[++num]=i;
		if(i*(ll)i!=C) d[++num]=C/i;
	}
//	sort(d+1,d+num+1);
	
	for(int i=1,now;i<=num;i++){
		now=d[i]-A%d[i];
		
		w=(A+now)*(ll)(B+now)/d[i];
		if(w<ans||(w==ans&&now<N)) N=now,ans=w;
	}
}

int main(){
	freopen("lcm.in","r",stdin);
	freopen("lcm.out","w",stdout);
	
	scanf("%d%d",&A,&B);
	if(A<B) swap(A,B);
	if(A==B){ puts("1"); return 0;}
	
	solve();
	
	cout<<N<<endl;
	return 0;
}