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>
#include <stdlib.h>

int max(int,int);

int main(int argc, char** argv) {
    int size;
    scanf("%d\n", &size);
    int array[size];
    
    for(int i = 0; i < size; i++)
        scanf("%d", &array[i]);
    
    int maxVal = array[1] - array[0];
    
    for(int i = 2; i < size; i++)
        for(int j = 0; j < i; j++)
            maxVal = max(maxVal, array[i] - array[j]);
    
    printf("%d\n", maxVal);
    
    return (EXIT_SUCCESS);
}

int max(int a, int b){
    if(a > b)
        return a;
    return b;
}