You have an integer variable x. Initially, x=0.

Some person gave you a string S of length N, and using the string you performed the following operation N times. In the i-th operation, you incremented the value of x by 1 if S_i=`I`, and decremented the value of x by 1 if S_i=`D`.

Find the maximum value taken by x during the operations (including before the first operation, and after the last operation).

Constraints

* 1≤N≤100
* |S|=N
* No characters except `I` and `D` occur in S.

Input

The input is given from Standard Input in the following format:


N
S


Output

Print the maximum value taken by x during the operations.

Examples

Input

5
IIDID


Output

2


Input

7
DDIDDII


Output

0
import java.util.Scanner;
 
public class Main {
 public static void main (String[ ] args) {
  Scanner sc = new Scanner(System.in);
  int n = sc.nextInt();
  String s = sc.next();
  char[] ch = s.toCharArray();
  int x = 0;
 
  int m = 0;
  for (int i = 0; i < n; i++) {
   if (ch[i] == 'I') {
    x++;
    m = Math.max(m, x);
   } else if (ch[i] == 'D') {
    x--;
   }
 }
 
 
  System.out.println(m);
 
 }
}