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{
	static Scanner s = new Scanner(System.in);
	public static void main(String[] args){
		s.next();
		String str=s.next();
		int cur=0,max=0;
		for(int i=0;i<str.length();i++) {
			switch (str.charAt(i)) {
			case 'D':
				cur--;
				break;
			case 'I':
				cur++;
				break;
			}
			max=Math.max(cur, max);
		}
		System.out.println(max);
	}
}
