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 as = new Scanner(System.in);
		int n=as.nextInt();
		String a = as.next();
		int l = 0;
		int s = 0;
		for(int i=0;i<n;i++){
			if(String.valueOf(a.charAt(i)).equals("I")){
				s++;
			}else{
				s--;
			}
			l = Math.max(l, s);
		}
		System.out.println(l);
	}
}