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 {

  public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);
	int n=sc.nextInt();
	int x=0;
	String str=sc.next();
	Set<Integer>set=new HashSet<>();
	set.add(0);
	for(int i=0;i<n;i++){
		if(str.charAt(i)=='I'){
			x++;
			set.add(x);
		}
		else {
			x--;
			set.add(x);
		}
	}
	System.out.println(Collections.max(set));
	sc.close();
  }
}
