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.*;
import static java.lang.System.*;
import static java.lang.Math.*;
public class Main {
public static void main(String[] args){
Scanner sc = new Scanner(in);
    int n = Integer.parseInt(sc.next());
    String s=sc.next();
    int x=0,max=0;
    for (int i = 0; i < n; i++) {
        if(s.charAt(i)=='I'){
            x++;
        }else{
            x--;
        }
        max=max(max,x);
    }
    out.println(max);
}}