Problem:
MathJax.Hub.Config({ tex2jax: { inlineMath: [["$","$"], ["\\(","\\)"]], processEscapes: true }});

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)

// Getting Started - Maximum Profit
// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_1_D
using System;
using System.Linq;

namespace ALDS1_1_D {
	class Program {
		public Program() {}
		
		public static void Main() {
			new Program().Calc();
		}
		
		void Calc() {
			var N = int.Parse(Input);	// Number of elements
			int min = int.Parse(Input);
			int max = -min;
			
			for(int i = 1; i < N; i ++) {
				int r = int.Parse(Input);
				if(max < r - min) max = r - min;
				if(min > r) min = r;
			}
			
			Output(max.ToString());
		}
		
		String Input {
			get {
				return Console.ReadLine();
			}
		}
		
		void Output(String str) {
			Console.WriteLine(str);
		}
	}
}