#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;
// random_device rd;
// mt19937 mt(rd());
// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// #include <boost/numeric/interval.hpp>
// #include <boost/numeric/interval/io.hpp>
// #include <boost/intrusive/rbtree.hpp>
// #include <boost/geometry.hpp>
// #include <boost/geometry/geometries/linestring.hpp>
// #include <boost/geometry/geometries/polygon.hpp>
// #include <boost/geometry/geometries/point_xy.hpp>
// namespace mp = boost::multiprecision;
// typedef mp::number<mp::cpp_dec_float<0>> cfloat;
// 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>
using namespace __gnu_pbds;
template<typename T=long long>using pbds=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
template<typename T=long long>using pqueue =__gnu_pbds::priority_queue<T, less<T>,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 output(v) do{bool f=0;for(auto i:v){cout<<(f?" ":"");if(i>INF/2)cout<<"INF";else cout<<i;f=1;}cout<<"\n";}while(0)
#define output2(v) for(auto j:v)output(j);
#define _output(v) do{bool f=0;rep(i,v.size()){cout<<(f?" ":"");if(v[i]>INF/2)cout<<"INF";else cout<<v[i];f=1;}cout<<"\n";}while(0)
#define _output2(v) rep(j,v.size()){_output(v[j]);}
#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 1000000007
#define endl "\n"
template<typename T=lint>T in(){return *istream_iterator<T>(cin);}
inline lint gcd(lint a,lint b){return b?gcd(b,a%b):a;}
inline lint lcm(lint a,lint b){return a*b/gcd(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<lint> dx={-1,1,0,0,1,1,-1,-1};
vector<lint> dy={0,0,-1,1,1,-1,1,-1};

template<class T> class Property{
public:
    T& r;
    std::function<void(T value)> set = nullptr; // ★追加
    std::function<T()> get = nullptr; // ★追加
    operator T(){
        return get ? this->get() : this->r;
    }

    // 直接中身を参照できるようにアロー演算子もオーバーロード
    T operator ->(){
        return get ? this->get() : this->r;
    }
    void operator =(const T v){
        if (set)this->set(v);
        else r = v;
    }
};


template<typename T,typename E=T>
struct treap{
    using F=function<E(E,E)>;
    vector<F> func;
    struct node{
        unsigned long xor128() {
            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)) );
        }
        node* ch[2]={nullptr,nullptr};
        T key;
        E val;
        vector<E> vals;
        lint pri=xor128(),cnt=1;
        node(T key,E val,int sz):key(key),val(val){vals.resize(sz);}
    };
    template<typename... F>
    treap(F... f){
        func.insert(func.end(),{f...});
    }
    node *root=nullptr;
    void insert(T key){
        emplace(key,key);
    }
    void emplace(T key,E val){
        auto d=split(root,lower_bound(root,key));
        root=merge(merge(d.first,new node(key,val,func.size())),d.second);
    }
    size_t size(){
        return count(root);
    }
    void erase_all(T key){
        auto d=split(root,upper_bound(root,key));
        root=merge(split(d.first,lower_bound(d.first,key)).first,d.second);
    }
    void erase(T key){
        if(get(lower_bound(root,key))!=key)return;
        auto d=split(root,lower_bound(root,key));
        root=merge(d.first,split(d.second,1).second);
    }
    vector<E> operator ()(const int& l,const int& r){
        auto s=split(root,lower_bound(root,l));
        auto t=split(s.second,lower_bound(s.second,r));
        vector<E>res;
        if(t.first)res=t.first->vals;
        root=merge(s.first,merge(t.first,t.second));
        return res;
    }
    E operator[](const int& k){
        pair<node*,node*>s,t;
        E& res=(t=split((s=split(root,k)).second,1)).first->val;
        root=merge(s.first,merge(t.first,t.second));
        return res;
    }
    int lower_bound(T k){return lower_bound(root,k);}
    private:
    int count(node* t){return !t?0:t->cnt;}
    node* update(node*& t){
        t->cnt=count(t->ch[0])+count(t->ch[1])+1;
        for(int i=0;i<(int)func.size();i++){
            t->vals[i]=t->val;
            if(t->ch[0])t->vals[i]=(func[i])(t->vals[i],t->ch[0]->vals[i]);
            if(t->ch[1])t->vals[i]=(func[i])(t->vals[i],t->ch[1]->vals[i]);
        }
        return t;
    }
    node* merge(node* l,node* r){
        if(!l||!r)return !l?r:l;
        if(l->pri>r->pri){
            l->ch[1]=merge(l->ch[1],r);
            return update(l);
        }else{
            r->ch[0]=merge(l,r->ch[0]);
            return update(r);
        }
    }
    //kより小さい値の数
    size_t lower_bound(node* t,T k){
        if(!t)return 0;
        else if(k<=(t->key))return lower_bound(t->ch[0],k);
        else return count(t->ch[0])+1+lower_bound(t->ch[1],k);
    }
    //k以下の値の数
    size_t upper_bound(node* t,T k){
        if(!t)return 0;
        else if(k<(t->key))return upper_bound(t->ch[0],k);
        else return count(t->ch[0])+1+upper_bound(t->ch[1],k);
    }
    //0-indexedでk番目から右側に
    pair<node*,node*> split(node* t,int k){
        if(!t)return make_pair(nullptr,nullptr);
        if(k<=count(t->ch[0])){
            auto s=split(t->ch[0],k);
            t->ch[0]=s.second;
            return make_pair(s.first,update(t));
        }else{
            auto s=split(t->ch[1],k-count(t->ch[0])-1);
            t->ch[1]=s.first;
            return make_pair(update(t),s.second);
        }
    }
};

int main(){
    lint n;
    cin>>n;
    treap<lint> t([](lint s,lint t){return gcd(s,t);});
    rep(i,n){
        lint x;
        cin>>x;
        t.emplace(i,x);
    }
    lint mx=0;
    rep(i,n){
        lint ans=0;
        if(t(0,i).size())ans=gcd(ans,t(0,i)[0]);
        if(t(i+1,n).size())ans=gcd(ans,t(i+1,n)[0]);
        chmax(mx,ans);
    }
    cout<<mx;
}

Measured memory_bytes: 11264