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.*;
// warm-up
public class Main {

	static void solve() {
		Scanner sc = new Scanner(System.in);
		int max = Integer.MIN_VALUE, t=0;
		sc.nextInt();
		for (char ch : sc.next().toCharArray()) {
			t+=ch=='I' ? 1 : -1;
			max=(t>max) ? t : max;
		}
		System.out.println(Math.max(max, 0));
		sc.close();			
	}

	public static void main(String args[]) {
		solve();
	}

}