#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int T;
bitset<1<<24> B;
vector<ll> V;
void solve() {
	int i,j,k,l,r,x,y; string s;
	
	for(i=2;i<=10000010;i++) if(B[i]==0) {
		for(j=i*2;j<=10000010;j+=i) B[j]=1;
		if(i>=5&&B[i]==0&&B[i-2]==0) {
			V.push_back(1LL*i*(i-2));
		}
	}
	
	cin>>T;
	while(T--) {
		ll N;
		cin>>N;
		x=lower_bound(ALL(V),N+1)-V.begin();
		if(x==0) {
			cout<<-1<<endl;
		}
		else {
			cout<<V[x-1]<<endl;
		}
	}
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}