Classical?

有 $n$ 个整数 $a_1,a_2,\cdots,a_n$，求$\max\limits_{1 \le i < j \le n} \left(\operatorname{lcm}(a_i,a_j)\right)$。 注：$\operatorname{lcm}(x,y)$ 即 $x,y$ 的最小公倍数。

Given an array $ a $ , consisting of $ n $ integers, find: $ $$$\max\limits_{1 \le i < j \le n} LCM(a_i,a_j), $ $ </p><p>where $ LCM(x, y) $ is the smallest positive integer that is divisible by both $ x $ and $ y $ . For example, $ LCM(6, 8) = 24 $ , $ LCM(4, 12) = 12 $ , $ LCM(2, 3) = 6$$$.

The first line contains an integer $ n $ ( $ 2 \le n \le 10^5 $ ) — the number of elements in the array $ a $ . The second line contains $ n $ integers $ a_1, a_2, \dots, a_n $ ( $ 1 \le a_i \le 10^5 $ ) — the elements of the array $ a $ .

Print one integer, the maximum value of the least common multiple of two elements in the array $ a $ .

3
13 35 77

1001

6
1 2 4 8 16 32

32