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) {

		try (Scanner sc = new Scanner(System.in)) {
			int N = sc.nextInt();
			String S = sc.next();

			int res = 0;
			int count = 0;
			for (int i = 0; i < N; i++) {
				if ('I' == S.charAt(i))
					count++;
				else
					count--;
				res = Math.max(res, count);
			}

			System.out.println(res);
		} // Scanner Close

	}
}
