#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ll long long
#define mod 998244353
int main(){
    cin.tie(0)->sync_with_stdio(0);
    cout.tie(0);
    bool deleted[10000007];
    for(int i=2;i<=10000000;i++) deleted[i]=true;
    for(int i=2;i<=10000;i++){
        if(deleted[i]==false) continue;
        for(int j=i*2;j<=10000000;j+=i) deleted[j]=false;
    }
    vector<ll>dat;
    for(ll i=3;i<=10000000;i+=2){
        if(deleted[i]==true && deleted[i+2]==true){
            dat.push_back(i*(i+2));
        }
    }
    ll T;
    cin>>T;
    for(int i=1;i<=T;i++){
        ll N;
        cin>>N;
        auto iter=upper_bound(dat.begin(),dat.end(),N);
        if(iter==dat.begin()) cout<<-1<<endl;
        else{
            iter--;
            cout<<*iter<<endl;
        }
    }
}