/*Md: Shamim Imtiaz*/

#include<bits/stdc++.h>

using namespace std;

/*-----------------------------*/
#define  READ   freopen("C:\\Users\\Lab1\\Desktop\\input.txt","r",stdin)
#define  WRITE  freopen("C:\\Users\\Lab1\\Desktop\\output.txt","w",stdout)
#define  _cin   ios_base::sync_with_stdio(0); cin.tie(0);

#define sc scanf
#define ll long long int
#define ull unsigned long long int
#define sc1(a) scanf("%lld",&a)
#define sc2(a,b) scanf("%lld%lld",&a,&b)
#define scu1(a) scanf("%llu",&a)
#define scu2(a,b) scanf("%llu%llu",&a,&b)
#define sci1(a) scanf("%d",&a)
#define sci2(a,b) scanf("%d%d",&a,&b)

#define mx 200000LL
#define mod 1000000007LL
#define eps 0.0000001
#define inf 999999999999999LL
#define pi 2*acos(0.00)
#define pb(a) push_back(a)
#define mem(a) memset(a,0,sizeof a)

#define fr1(n,i) for(int i=1; i<=n; i++)
#define fr0(n,i) for(int i=0; i<n; i++)

#define pf printf
#define pf1(a) printf("%lld\n",a)
#define pf2(a,b) printf("%lld %lld\n",a,b)
#define pfi1(a) printf("%d\n",a)
#define pfi2(a,b) printf("%d %d\n",a,b)
#define pfu1(a) printf("%llu\n",a)
#define pfu2(a,b) printf("%llu %llu\n",a,b)

#define w1(a) while(scanf("%lld",&a)==1)
#define w2(a,b) while(scanf("%lld%lld",&a,&b)==2)
#define wi1(a) while(scanf("%d",&a)==1)
#define wi2(a,b) while(scanf("%d%d",&a,&b)==2)
#define wu1(a) while(scanf("%llu",&a)==1)
#define wu2(a,b) while(scanf("%llu%llu",&a,&b)==2)

/*-----------------------------*/

ll p4[]= {-1,1,0,0};
ll q4[]= {0,0,1,-1};
ll p8[]= {-1,1,0,0,-1,1,-1,1};
ll q8[]= {0,0,1,-1,1,1,-1,-1};

ll  gcd(ll a, ll b)
{
    if(b>a)gcd(b,a);
    return ((b==0)?a:gcd(b,a%b));
}

ll  LCM(ll a, ll b)
{
    ll p=(a*b)/(gcd(a,b));
    return p;
}

ll BigMod(ll a, ll b, ll m)
{
    if(!b)return 1;
    ll ans = BigMod(a, b/2, m);
    ans = (ans*ans)%m;
    if(b&1)
        ans = (ans*a)%m;
    return ans;
}

ll Mod_inv(ll a)
{
    return BigMod(a,mod-2,mod);
}

ll arra[47000+5],arre[47000+5];
ll pl=0;//prime length
void prime_factor()
{
    arre[0]=1;
    arre[1]=1;
    for(int i=2; i<=47000; i++)
    {
        if(arre[i]==0)
        {
            for(int j=i; j<=47000; j=j+i)
            {
                arre[j]=1;
            }
            arra[pl++]=i;
        }
    }
}
ll prime(ll a)
{
    prime_factor();
    ll i;
    if(a==1)
        return 1;
    else if(a==2)
        return 0;
    else if(a%2==0)
        return 1;
    else
        for(i=1 ; i<pl && (arra[i]*arra[i]<=a) ; i++)
        {
            if(a%arra[i]==0)
                return 1;
        }
    return 0;
}

/*-----------------------------*/

int main()
{
    ll a[100005],i,j,k,p,q,x,y,n,m,c,f;
    vector<ll>v;
    while(cin >> n)
    {
        for(i=0; i<n; i++)
        {
            cin >> a[i];
        }
        f=0;
        if(n==1)
        {
            cout << n+1 << endl;
            continue;
        }
        if(n==2)
        {
            cout << max(a[0],a[1]) << endl;
            continue;
        }
        for(i=0; i<n-1; i++)
        {
            x=gcd(a[i],a[i+1]);
            if(x!=1&&x!=0)
            {
                v.pb(x);
            }
        }
        sort(v.begin(),v.end());
        for(j=0; j<n-1; j++)
        {
            p=0;
            q=v[j];
            for(i=0; i<n; i++)
            {
                if(a[i]%q!=0)
                {
                    p++;
                }
                if(p>1)
                    break;
            }
            if(p==1)
            {
                cout << q << endl;
                f=1;
                break;
            }
        }
        if(f==0)
        {
            for(j=2; j<n; j++)
            {
                p=0;
                for(i=0; i<n; i++)
                {
                    if(a[i]%j!=0)
                    {
                        p++;
                    }
                    if(p>1)
                        break;
                }
                if(p==1)
                {
                    cout << q << endl;
                    break;
                }
            }
        }
    }
    return 0;
}