#include <bits/stdc++.h>
using namespace std;
int ans = 0;
int a[200008];
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  for (int i = 0; i < n - 1; i++)
    if (i == 0 || a[i] != a[i - 1]) {
      int j = a[i] + a[i], p;
      while (j <= a[n - 1]) {
        p = lower_bound(a, a + n, j) - a;
        ans = (ans < a[p - 1] % a[i]) ? a[p - 1] % a[i] : ans;
        j += a[i];
      }
      ans = (ans < a[n - 1] % a[i]) ? a[n - 1] % a[i] : ans;
    }
  cout << ans << endl;
  return 0;
}

### Prompt

In CPP, your task is to solve the following problem:

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

Input

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

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

Output

Print the answer to the problem.

Examples

Input

3
3 4 5


Output

2

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int ans = 0;
int a[200008];
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  for (int i = 0; i < n - 1; i++)
    if (i == 0 || a[i] != a[i - 1]) {
      int j = a[i] + a[i], p;
      while (j <= a[n - 1]) {
        p = lower_bound(a, a + n, j) - a;
        ans = (ans < a[p - 1] % a[i]) ? a[p - 1] % a[i] : ans;
        j += a[i];
      }
      ans = (ans < a[n - 1] % a[i]) ? a[n - 1] % a[i] : ans;
    }
  cout << ans << endl;
  return 0;
}

```