import sys
input = sys.stdin.readline

from bisect import bisect

x=10**7+20    
import math 
L=math.floor(math.sqrt(x)) # 平方根を求める

Primelist=[i for i in range(x+1)]
Primelist[1]=0 # 1は素数でないので0にする.
 
for i in Primelist:
    if i>L:
        break
    if i==0:
        continue
    for j in range(2*i,x+1,i):
        Primelist[j]=0

Primes=[Primelist[j] for j in range(x+1) if Primelist[j]!=0]
SP=set(Primes)

X=[]

for i in range(len(Primes)-1):
    if Primes[i+1]==Primes[i]+2:
        X.append(Primes[i]*Primes[i+1])
T=int(input())
for tests in range(T):
    N=int(input())

    x=bisect(X,N)

    ANS=-1

    for i in range(x-2,min(len(X),x+3)):
        if X[i]<=N:
            ANS=X[i]

    print(ANS)