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 JAVA (judge verdict: Wrong Answer)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Scanner;
import java.util.StringTokenizer;
import java.math.BigDecimal;

public class Main {
  static InputReader in;
  static PrintWriter out;

  static class Solution {
    void solve() throws IOException {
      int n = in.nextInt();
      int[] R = new int[n];
      int max = 0;
      
      
      for (int i = 0; i < n; i++) {
        R[i] = in.nextInt();
      }
      int min = R[0];
      
      for (int j = 1; j < n; j++) {
       max = Math.max(max, R[j] - min);
       min = Math.min(min, R[j]);
      }
      
      out.println(max);
//      End solve()
    }
    
    
    
//    End Solution
}


  public static void main(String[] args) throws IOException {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out);
    Solution solver = new Solution();
    solver.solve();
    out.close();
}


  static class InputReader {
    public BufferedReader br;
    public StringTokenizer st;

    public InputReader(InputStream stream) {
      br = new BufferedReader(new InputStreamReader(stream));
    }

    public int nextInt() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    }

    public long nextLong() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    }

    public String next() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    }

    public double nextDouble() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    }

  }

}