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;


	public class Max
	{
		public static void Main(string[] args)
		{
			int count=int.Parse(Console.ReadLine());
			
			int[] ex=new int[count];
			for(int k=0;k<count;k++)
			{
				ex[k]=int.Parse(Console.ReadLine());
			}
			int max=ex[count-1]-ex[count-2];//for?????????????????????????????????
			for(int i=0;i<count-2;i++)
			{
				for(int j=i+1;j<count;j++)
				{
					//??????????????????????§???????????????????????????????????????????max??????????????????
					if(max<ex[j]-ex[i])
					{
						max=ex[j]-ex[i];
					}
					
				}
			}
			Console.WriteLine(max);
		}
	}