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

}