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<stdio.h>
#define A 200000
int main(){
	
    int n,i,j,k;
    int R[A];
    
	/* nを格納 */
    scanf("%d",&n);
	
	/* R[i]をn個格納 */
    for(i=0;i<n;i++){
        scanf("%d",&R[i]);
    }
     
    for(i=0;i<n-1;i++){
    	
        if(i==0||j>R[i]){/* 最小値を探し、jに格納 */
            j=R[i];
        }
        if(i==0||k<R[i+1]-j){/* 差の値の大きい方を格納 */
            k=R[i+1]-j;
        }
    }
	
    printf("%d\n",k);/* 最大の差を格納 */
     
    return 0;
}