Minimum Moves to Non-Decreasing Sequence

You are given a sequence of n integers. Your task is to determine the minimum number of moves required to transform this sequence into a non-decreasing sequence.

In one move, you can increment an element by exactly one. More formally, given a sequence \(a_1, a_2, \dots, a_n\), you need to ensure that \(a_1 \le a_2 \le \dots \le a_n\). The total number of moves required is the sum of all necessary increments:

\(\text{moves} = \sum_{i=2}^{n} \max(0, a_{i-1} - a_i)\)

Help the judge determine the minimum number of moves required to achieve this non-decreasing order.

inputFormat

The input is provided via standard input and has the following format:

n
x1 x2 x3 ... xn

Where:

• n is the number of elements in the sequence.
• x1, x2, ..., xn are the integers in the sequence (separated by spaces).

outputFormat

Output a single integer which is the minimum number of moves required to make the sequence non-decreasing. The output should be printed to standard output.

## sample

5
4 2 1 3 5

6