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;

public class Hello
{
    public static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        int[] R = new int[n];
        for(int a = 0; a < n; a++)
        {
            R[a] = int.Parse(Console.ReadLine());
        }
        int minV = R[0];
        int maxV = -1000000000;
        for(int j = 1; j < n; j++)
        {
           minV = Math.Min(minV, R[j - 1]);
           maxV = Math.Max(R[j] - minV, maxV);
           
        }
        Console.WriteLine(maxV);
    }
}