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, maxv, minv;
 int R[A];
 scanf("%d" , &n);
 
 for(i=0; i<n; i++){
  scanf("%d" , &R[i]);
  }
  
  for(i=0; i<n-1; i++){
   if(i==0 || minv>R[i]){
     minv=R[i];
     }
  if(i==0 || maxv<R[i+1]-minv){
     maxv=R[i+1]-minv;
     }
 }
  
 printf("%d\n" , maxv);
 
 return 0;
 }