package main

import . "fmt"
import . "sort"
import . "os"
import bf "bufio"

func main() {
	sv:=make([]bool,1e7+4)
	pr:=make([]int,0,6e6)
	sv[1]=true
	for i:=3;i<len(sv);i+=2 {
		if sv[i] {
			continue
		}
		if !sv[i-2] {
			pr=append(pr,(i-2)*i)
		}
		for j:=i+i;j<len(sv);j+=i {
			sv[j]=true
		}
	}
	rd:=bf.NewReader(Stdin)
	wr:=bf.NewWriter(Stdout)
	defer wr.Flush()
	var t int
	Fscan(rd,&t)
	for ;t>0;t-- {
		var n int
		Fscan(rd,&n)
		i:=SearchInts(pr,n)
		if i>=len(pr) {
			i--
		}
		if i>=0 && pr[i]<=n {
			Fprintln(wr,pr[i])
		} else if i>0&&pr[i-1]<=n {
			Fprintln(wr,pr[i-1])
		} else {
			Fprintln(wr,-1)
		}
	}
}