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.*;
public class Main {
	public static void main(String[] args){
	Scanner sc = new Scanner(System.in);
	int N = sc.nextInt();
	String S = sc.next();
	int max = 0;
	int count = 0;
	String S_split[] = S.split("");
	for(int i = 0;i < S_split.length;i++){
		if(S_split[i].equals("I")){
			count += 1;
			max = Math.max(max,count);			
		}else if(S_split[i].equals("D")){
			count -= 1;			
			max = Math.max(max,count);
		}
	}
	System.out.println(max);
	}
}
	

