#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=2167167167167167167;
const int INF=2100000000;
const int mod=998244353;
#define rep(i,a,b) for (ll i=a;i<b;i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}
template<class T> void vec_out(vector<T> &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){assert(!a.empty());T ans=a[0]-a[0];for(auto &x:a) ans+=x;return ans;}



void solve();
// oddloop
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t=1;
	//cin>>t;
	rep(i,0,t) solve();
}

void solve(){
	int L=3e4+10;
	vector<bool> A(L),B(L);
	int N,M;
	cin>>N>>M;
	rep(i,0,N){
		int a;
		cin>>a;
		A[a]=1;
	}
	rep(i,0,M){
		int a;
		cin>>a;
		B[a]=1;
	}
	if(!(A[1]&B[1])){
		cout<<"1\n";
		return;
	}
	int X=2;
	while(A[X]|B[X]) X++;
	vector<int> lis(X*2+1);
	vector<vector<int>> p(X*2+1),q(X*2+1);
	rep(i,1,X){
		int a=(i-(X*X)%i)%i;
		while(a<=X*2){
			p[a].push_back(i);
			q[a].push_back((X*X+a)/i);
			a+=i;
		}
	}
	p[0].push_back(X);
	p[X].push_back(X);
	p[X].push_back(X+1);
	rep(i,0,X*2+1){
		reverse(all(q[i]));
		for(auto x:q[i]) p[i].push_back(x);
	}
	auto f=[&](int a)->int{
		int l=0,r=L;
		while(r-l>1){
			int med=(l+r)/2;
			if(a<med*med) r=med;
			else l=med;
		}
		return l;
	};
	rep(i,0,X*2+1){
		bool ok=0;
		int len=p[i].size();
		rep(j,0,len){
			if(A[f(p[i][j])]&B[f(p[i][len-1-j])]) ok=1;
		}
		if(ok) continue;
		cout<<X*X+i<<endl;
		return;
	}
}