#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
using namespace::std;
//struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}} __init;
__attribute__((constructor))
void init(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(15);
}
// random_device rd;
// mt19937 mt(rd());
// #include <boost/numeric/interval.hpp>
// #include <boost/numeric/interval/io.hpp>
// #include <boost/intrusive/rbtree.hpp>
// #include <boost/dynamic_bitset.hpp>
// #include <boost/geometry.hpp>
// #include <boost/geometry/geometries/linestring.hpp>
// #include <boost/geometry/geometries/polygon.hpp>
// #include <boost/geometry/geometries/point_xy.hpp>
// #include <boost/math/tools/minima.hpp>
// using boost::math::tools::brent_find_minima;
// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// typedef mp::number<mp::cpp_dec_float<256>> cdouble;
// typedef mp::cpp_int cint;

#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/priority_queue.hpp>
#include<ext/pb_ds/tag_and_trait.hpp>
template<typename T=long long>using pbds=__gnu_pbds::tree<T,__gnu_pbds::null_type,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T=long long>using pbds_map=__gnu_pbds::tree<T,T,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T=long long>using pqueue =__gnu_pbds::priority_queue<T, less<T>,__gnu_pbds::rc_binomial_heap_tag>;
typedef long long lint;
typedef long long ll;
typedef long double ldouble;
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<double> dvec;
typedef vector<vector<double>> dmat;
typedef vector<vector<vector<double>>> dmat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
typedef vector<vector<vector<string>>> smat3;
typedef vector<pair<lint,lint>> pvec;
typedef vector<vector<pair<lint,lint>>> pmat;
typedef vector<vector<vector<pair<lint,lint>>>> pmat3;
#define rep(i, n) for(lint i = 0; i < (lint)(n); i++)
#define irep(i) for(lint i = 0;; i++)
#define irep1(i) for(lint i = 1;; i++)
#define irep2(i) for(lint i = 2;; i++)
#define rrep(i, n) for(lint i = (lint)(n-1); i >-1; i--)
#define rrepi(i,a,b) for(lint i = (lint)(b-1); i >a-1; i--)
#define repi(i,a,b) for(lint i=lint(a);i<lint(b);i++)
#define rep2(i,a,b,c) for(lint i=lint(a);i>lint(b);i+=c)
#define all(x) (x).begin(),(x).end()
#define PI 3.141592653589793
#define dist(x1,y1,x2,y2) (pow(pow(x2-x1,2)+pow(y2-y1,2),0.5))
#define input(a,n) lint n;cin>>n;vector<lint>a(n);rep(i,n)cin>>a[i];
#define SUM(v) accumulate(all(v),0LL)
#define INF (1LL<<60)
#define IINF (1<<30)
#define EPS (1e-10)
#define LINF 9223372036854775807
//#define MOD 998244353LL
//#define MOD 1000000007LL
#define endl "\n"
template<typename T>inline void numout(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i<INF/2?i:"INF";f=1;}cout<<endl;}
template<typename T>inline void numout2(T t){for(auto i:t)numout(i);}
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void _output(T t){bool f=0;for(int i=0;i<t.size();i++){cout<<f?"":" "<<t[i];f=1;}cout<<endl;}
template<typename T>inline void _output2(T t){for(int i=0;i<t.size();i++)output(t[i]);}
auto Y=[&](auto f){return[&](auto... args){return f(f, args...);};};
template<typename T=lint>T in(){return *istream_iterator<T>(cin);}
template<typename T=lint>inline T gcd(T a,T b){return b?gcd(b,a%b):a;}
template<typename T=lint>inline T lcm(T a,T b){return a/gcd(a,b)*b;}
template<typename T=lint>inline T minq(T a,T b){return min(a,b);}
inline bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
inline bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
vector<int> dx={-1,1,0,0,1,1,-1,-1};
vector<int> dy={0,0,-1,1,1,-1,1,-1};



template<typename T,typename E>
class RBST{
    inline unsigned long rnd() {
        static unsigned long x=123456789, y=362436069, z=521288629, w=88675123;
        unsigned long t=(x^(x<<11));
        x=y; y=z; z=w;
        return ( w=(w^(w>>19))^(t^(t>>8)) );
    }
    struct node;
    using np=node*;
    struct node{
        node* ch[2]={nullptr,nullptr};
        T key;E val;E cal;
        int cnt=1;
        node(T key,E val):key(key),val(val){}
    };
    np root=nullptr;
    using F=function<E(E,E)>;
    E e=NULL;
    F func=NULL;
    inline int count(np t){return !t?0:t->cnt;}
    np update(np& t){
        t->cnt=count(t->ch[0])+count(t->ch[1])+1;
        if(func){
            t->cal=e;
            if(t->ch[0])t->cal=func(t->cal,t->ch[0]->cal);
            t->cal=func(t->cal,t->val);
            if(t->ch[1])t->cal=func(t->cal,t->ch[1]->cal);
        }
        return t;
    }
    public:
    RBST(){}
    RBST(E e,F f):e(e),func(f){}
    void insert(T key,E val){insert(root,key,val);}
    void erase(T key){erase(root,key);}
    void erase_all(T key){erase(root,key);}
    int lower_bound(T k){return lower_bound(root,k);}
    int upper_bound(T k){return upper_bound(root,k);}
    T find_key_by_order(T k){return find_key_by_order(root,k);}
    E find_by_order(int idx){return find_by_order(root,idx);}
    E get_sum(T l,T r){return get_sum(root,l,r);}
    E get_sum_by_order(int l,int r){return get_sum_by_order(root,l,r);}
    int size(){return count(root);}
    private:
    void insert(np& t,T key,E val){
        np p=new node(key,val);
        auto d=split(t,lower_bound(t,key));
        t=merge(d.first,merge(update(p),d.second));
    }
    np erase(np& t,T key){
        int idx=lower_bound(t,key);
        auto d=split(t,idx,idx+1);
        t=merge(get<0>(d),get<2>(d));
    }
    np erase_all(np& t,T key){
        auto d=split(t,lower_bound(t,key),upper_bound(t,key));
        t=merge(get<0>(d),get<2>(d));
    }
    E get_sum(np& t,T l,T r){
        np x,y,z;
        tie(x,y,z)=split(t,l,r);
        E res;
        if(y)res=y->cal;
        else res=e;
        t=merge(x,y,z);
        return res;
    }
    E get_sum_by_order(np& t,int l,int r){
        np x,y,z;
        tie(x,y,z)=split_by_order(t,l,r);
        E res;
        if(y)res=y->cal;
        else res=e;
        t=merge(x,y,z);
        return res;
    }
    T find_key_by_order(np& t,const int& k){
        np p,q,r;
        tie(p,q,r)=split(t,k,k+1);
        if(q){
            t=merge(p,q,r);
            return q->key;
        }
    }
    T find_by_order(np& t,const int& k){
        np p,q,r;
        tie(p,q,r)=split(t,k,k+1);
        if(q){
            t=merge(p,q,r);
            return q->val;
        }
        return -1;
    }
    int lower_bound(np& t,T k){
        if(!t)return 0;
        if(k<=(t->key))return lower_bound(t->ch[0],k);
        else return count(t->ch[0])+1+lower_bound(t->ch[1],k);
    }
    int upper_bound(np& t,T k){
        if(!t)return 0;
        if(k<(t->key))return upper_bound(t->ch[0],k);
        else return count(t->ch[0])+1+upper_bound(t->ch[1],k);
    }
    np merge(np& p,np& q,np& r){
        return merge(p,merge(q,r));
    }
    np merge(np l,np r){
        if(!l||!r)return !l?r:l;
        if((unsigned long)count(l)>rnd()%(unsigned long)(count(l)+count(r))){
            l->ch[1]=merge(l->ch[1],r);
            return update(l);
        }else{
            r->ch[0]=merge(l,r->ch[0]);
            return update(r);
        }
    }
    tuple<np,np,np> split(np t,T l,T r){
        auto p=split(t,l);
        auto q=split(p.second,r);
        return make_tuple(p.first,q.first,q.second);
    }
    pair<np,np> split(np t,T k){
        if(!t)return make_pair(nullptr,nullptr);
        bool b=k>t->key;
        auto s=split(t->ch[b],k);
        t->ch[b]=b?s.first:s.second;
        return b?make_pair(update(t),s.second):make_pair(s.first,update(t));
    }
    //0-indexed [-INF,l),[l,r),[r,INF)
    tuple<np,np,np> split_by_order(np t,int l,int r){
        auto p=split_by_order(t,l);
        auto q=split_by_order(p.second,r-l);
        return make_tuple(p.first,q.first,q.second);
    }
    //0-indexed [-INF,k),[k,INF)
    inline pair<np,np> split_by_order(np t,int k){
        if(!t)return make_pair(nullptr,nullptr);
        bool b=k>count(t->ch[0]);
        auto s=split_by_order(t->ch[b],k-(b?(count(t->ch[0])+1):0));
        t->ch[b]=b?s.first:s.second;
        return b?make_pair(update(t),s.second):make_pair(s.first,update(t));
    }
};
 

int main(){
    lint n;
    cin>>n;
	RBST<lint,lint>v(0LL,[](auto s,auto t){return gcd(s,t);});
    rep(i,n){
        lint x;
        cin>>x;
        v.insert(i,x);
    }
    lint mx=0;
    v.get_sum_by_order(2,3);
    rep(i,n){
        chmax(mx,gcd(v.get_sum_by_order(0,i),v.get_sum_by_order(i+1,n)));
    }
    cout<<mx<<endl;
}

Measured memory_bytes: 6528