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(){
	long i, n, maxv, minv, num;

	scanf("%ld", &n);
	scanf("%ld", &minv);
	scanf("%ld", &num);
	maxv = num - minv;
	if(minv >= num){
		minv = num;
	}
	else{
		//none
	}

	for( i=1; i<(n-1); i++	){
		scanf("%ld", &num);
		if( maxv <= (num - minv) ){
			maxv = (num - minv);
		}
		else{
			//none
		}

		if( minv >= num){
			minv = num;
		}
		else{
			//none
		}
	}

	printf("%ld\n", maxv);

	return 0;
}