Given an array ~a~ consisting of ~n~ elements, ~a_1, a_2, . . . , a_n~. Find the maximum value of ~a_i~ mod ~a_j~ with ~1 ≤ i, j ≤ n~ and ~a_i ≥ a_j~.

Input

The first line contains ~a~ positive integer ~n~ ~(n ≤ 10^5)~, which is the number of elements in the array ~a~.

The second line contains ~n~ values ~a_1, a_2,..., a_n~ ~(1 ≤ ai ≤ 10^6)~.

Output

A single integer is the result of the problem

Sample Input 1

9
1 2 3 4 5 6 7 8 9

Sample Ouput 1

4