import math
N,K=map(int,input().split())
A=list(map(int,input().split()))
d = N - N//K
dat = [0] * (max(A)+1)

def make_divisors(n):
    lower_divisors , upper_divisors = [], []
    i = 1
    while i*i <= n:
        if n % i == 0:
            lower_divisors.append(i)
            if i != n // i:
                upper_divisors.append(n//i)
        i += 1
    return lower_divisors + upper_divisors[::-1]

for a in A:
    for di in make_divisors(a):
        dat[di] += 1
#print(dat,d)
ans = 1
for i in range(len(dat)):
    if dat[i] > d:
        ans = math.lcm(ans, i)
print(ans)