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)

#include<stdio.h>

int main( void ) 
{
	int n;
	int nums[200000];
	int max,tnum;
	int i,j;

	scanf( "%d", &n );
	
  	max=1-1000000000;
	for( j=0; j<n; j++ ) {
  		scanf( "%d", &nums[j] );
		for( i=0; i<j; i++ ) {
			tnum=nums[j]-nums[i];
			if( max <= tnum ) {
				max=tnum;
			}
	  	}
  	}
	printf( "%d\n", max );

	return 0;
}