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 in=new Scanner(System.in);
int N=in.nextInt();
String dummy = in.nextLine();
String S=in.nextLine();
int x=0; int max=0;
for (int i=0; i<N; i++)
{
char c=S.charAt(i);
if(c=='I')
x++;
else
x--;
if(x>max)
max=x;
}
System.out.println(max);
}
}
