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 <iostream>
#include <algorithm>
using namespace std;
//static const int MIN = -2000000000;

int main() {
    // insert code here...
    int x;
    int n;
    int R[200000];
    int maxv;
    int minv;
    
    cin >> n;
    
    for (x=0; x<n; x++)
    {
        cin >> R[x];
    }
    
    maxv = -2000000000;
    minv = R[0];
    
    for (x=1; x<n; x++)
    {
        maxv = max(maxv,R[x]-minv);
        minv = min(minv,R[x]);
    }
    
    cout << maxv << endl;
    return 0;
}