#1165: Puzzle Games

Describe

Fragrance today is in a good mood, and the flowers in the field of insects play a puzzle game.
This game is like this, for an array A, fragrance Select a number a from a, insects select a number b from a. A and B can be the same. Their score is the number of a*b factors.
The delicate fragrance and the worm of course want to get as high a score as possible, can you tell them which two number to choose?
Since the fragrance is a very casual person, the elements in array A are randomly chosen by her.

Input

A row of number N, which represents the number of integers in a.
The next line of N is the number of A1,A2,..., an, respectively, as an element of a.

n <= 100000, 1 <= ai <= 100000
Ensure that all AI are randomly generated.

Output

A row represents the maximum score.

Sample input

23 4

Sample output

6

#1165: Puzzle Games