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: Accepted)

#include<iostream>
using namespace std;
int Max = 200000;

int main(){
  int A[Max], n, i;
  int maxv, minv;

  cin >> n;
  for(i = 0; i < n; i++) {
    cin >> A[i];
  }

  maxv = A[1] - A[0];
  minv = A[0];

  for(i = 1; i < n; i++) {
    maxv = (maxv > (A[i] - minv))?maxv:(A[i] - minv);
    minv = (minv < A[i])?minv:A[i];
  }

  cout<<maxv<<endl;

  return 0;

}