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 scan=new Scanner(System.in);
int n=scan.nextInt();
String s=scan.next();
int max=0;
int x=0;
for(int i=0;i<n;i++){
if(s.charAt(i)=='I'){
x++;
max=Math.max(x,max);
}else{x--;}
}
System.out.println(max);
}
}
