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)

#include <stdio.h>

int main(int argc, char** argv){
	int n,value;
	int base,max_diff;
	int i;

	// Input n + two number
	scanf("%d%d%d",&n, &base, &value);
	max_diff = value - base;
	if( value < base ) {
		base = value;
	}

	// Check Rest Number
	for(i=3;i<=n;i++){
		scanf("%d",&value);
		if( value - base > max_diff ){
			max_diff = value - base;
		}
		if( value < base ) {
			base = value;
		}
	}

	// Output
	printf("%d\n",max_diff);

	return 0;
}