Array

You are given an array $a\_1, a\_2, \ldots, a\_n$. Let $x\_1 = a\_1$, and $x\_i = x\_{i - 1} \bmod a\_i$ for each $i$ from $2$ to $n$.

Suppose that we can rearrange $a\_1, \ldots, a\_n$ in any way. What is the largest possible value of $x\_n$ we can obtain?

The first line contains an integer $n$ --- the size of the array ($2\leq n\leq 10^5$).

The second line containing $n$ integers $a\_1, \ldots, a\_n$ ($1\leq a\_i\leq 10^5$).

Print one integer --- the largest possible value of $x\_n$.