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: Time Limit Exceeded)

using System;

namespace AOJ
{
    class Program
    {
        static void Main(string[] args)
        {
            // 入力の数
            string inputLinesStr = Console.ReadLine();
            int inputLines = Int32.Parse(inputLinesStr);

            // 全ての入力
            int[] inputNums = new int[inputLines];

            for (int i = 0; i < inputLines; i++)
            {
                inputNums[i] = Int32.Parse(Console.ReadLine());
            }

            // 最大利益を調査
            int maxProfit = Int32.MinValue;

            for (int rightIndex = 0; rightIndex < inputLines - 1; rightIndex++)
            {
                for (int leftIndex = rightIndex + 1; leftIndex < inputLines; leftIndex++)
                {
                    if (maxProfit < (inputNums[leftIndex] - inputNums[rightIndex]))
                    {
                        maxProfit = inputNums[leftIndex] - inputNums[rightIndex];
                    }
                }
            }

            //Console.Write("最大利益は ");
            Console.WriteLine(maxProfit);
        }
    }
}