B. Maximum Value
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

You are given a sequence a consisting of n integers. Find the maximum possible value of (integer remainder of a i divided by a j), where 1 ≤ i, j ≤ n and a i ≥ a j.

Input

The first line contains integer n — the length of the sequence (1 ≤ n ≤ 2·105).

The second line contains n space-separated integers a i (1 ≤ a i ≤ 106).

Output

Print the answer to the problem.

Examples
Input
3
3 4 5
Output
2