Problem:
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Maximum Profit

You can obtain profits from foreign exchange margin transactions. For example, if you buy 1000 dollar at a rate of 100 yen per dollar, and sell them at a rate of 108 yen per dollar, you can obtain (108 - 100) × 1000 = 8000 yen.

Write a program which reads values of a currency $R_t$ at a certain time $t$ ($t = 0, 1, 2, ... n-1$), and reports the maximum value of $R_j - R_i$ where $j > i$ .

Input

The first line contains an integer $n$. In the following $n$ lines, $R_t$ ($t = 0, 1, 2, ... n-1$) are given in order.

Output

Print the maximum value in a line.

Constraints

$2 \leq n \leq 200,000$

$1 \leq R_t \leq 10^9$

Sample Input 1

6
5
3
1
3
4
3

Sample Output 1

3

Sample Input 2

3
4
3
2

Sample Output 2

-1

Solution in C# (judge verdict: Accepted)

using System;

class Program
{
    static int Main(string[] args)
    {
        //入力
        int inputCount = int.Parse(Console.ReadLine().Trim());

        int[] inputNum = new int[inputCount];
        for (int lp = 0; lp < inputCount; lp++)
        {
            inputNum[lp] = int.Parse(Console.ReadLine().Trim());
        }

        //string str = Console.In.ReadToEnd();
        //var lines = str.Split("\r\n".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);

        // 処理
        int minVal = inputNum[0];
        int profit = Int32.MinValue;

        for (int lp = 1; lp < inputCount; lp++)
        {
            if (profit < inputNum[lp] - minVal)
            {
                profit = inputNum[lp] - minVal;
            }
            if (inputNum[lp] < minVal)
            {
                minVal = inputNum[lp];
            }
        }

        Console.WriteLine(profit);
        return 0;
    }
}