# Getting Started - Maximum Profit

Time Limit : 1 sec, Memory Limit : 131072 KB
Japanese version is here

# 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