Maximum Value

题面翻译

• 给定一个序列 $a_i$，请找出两个数 $i,j$，使得 $a_i \ge a_j$，并且使得 $a_i \bmod a_j$ 的值最大，求这个 $a_i\bmod a_j$ 的最大值。
• 对于 $100\%$ 的数据，$1 \le n \le 2\times 10^5$，$1 \le a_i \le 10^6$。
• Translated by 一只书虫仔 & QwQcOrz。

题目描述

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 $a_{i}>=a_{j}$ .

输入格式

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 $a_{i}>=a_{j}$ .

输出格式

Print the answer to the problem.

样例 #1

样例输入 #1

3
3 4 5

样例输出 #1

2