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{

	static final Scanner	s	=new Scanner(System.in);

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

	private static void input(){
	}

	private static void solve(){
		int x=0,max=0;
		s.next();
		char in[]=s.next().toCharArray();
		for(char c:in) {
			x+=c=='I'?1:-1;
			max=Math.max(x,max);
		}
		System.out.println(max);
	}
}
