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>
#define BUF_SIZE 100
#define LONG_MIN -2147483646
#define LONG_MAX 2147483647

int main(void)
{
  char buf[100];
  long input, maxv = LONG_MIN, min = LONG_MAX;
  long linum;
  long diff = 0;

  linum = fgets(buf, BUF_SIZE, stdin);

  while(linum > 1){
    fgets(buf, BUF_SIZE, stdin);
    sscanf(buf, "%ld", &input);

    diff = input - min;
    if(maxv < diff){
      maxv = diff;
    }

    if(input < min){
      min = input;
    }
    linum--;
  }

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

  return 0;
}