#include <bits/stdc++.h>
using namespace std;
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n,cnt=0; cin>>n;
int arr[n];
for(int i=0;i<n;i++) cin>>arr[i];
for(int i=2;i<=10000;i++){
cnt=0;
for(int j=0;j<n;j++){
if(__gcd(arr[j],i)!=1) cnt++;
}
if(cnt==n){
cout<<i;
return 0;
}
}
return 0;
}
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