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;
 
class Main{
    static Scanner in = new Scanner(System.in);
     public static void main(String[] args){
         int i = Integer.parseInt(in.nextLine());
         String s = in.nextLine();
         int max = 0;
         i = 0;
         for(char c : s.toCharArray()){
             if(c == 'I'){
                 i++;
             }else{
                 i--;
             }
             max = Math.max(max, i);
         }
         System.out.println(max);
     }
}